Outline of underwater diving

The following outline is provided as an overview of and topical guide to underwater diving:

Underwater diving – as a human activity, is the practice of descending below the water's surface to interact with the environment.

What type of activity is underwater diving?

Underwater diving can be described as all of the following:

A human activity – intentional, purposive, conscious and subjectively meaningful sequence of actions. Underwater diving is practiced as part of an occupation, or for recreation, where the practitioner submerges below the surface of the water or other liquid for a period which may range between seconds to the order of a day at a time, either exposed to the ambient pressure or isolated by a pressure resistant suit, to interact with the underwater environment for pleasure, competitive sport, or as a means to reach a work site for profit or in the pursuit of knowledge, and may use no equipment at all, or a wide range of equipment which may include breathing apparatus, environmental protective clothing, aids to vision, communication, propulsion, maneuverability, buoyancy and safety equipment, and tools for the task at hand.

Diving activity, by type

Modes of underwater diving

Surface-supplied diver with helmet, bailout set and umbilical cable

There are several modes of diving distinguished by the equipment and procedures used:

Ambient pressure diving – Underwater diving where the diver is exposed to the ambient pressure
- Freediving – Underwater diving without breathing apparatus
- Scuba diving – Swimming underwater, breathing gas carried by the diver
  - Open-circuit scuba diving – Self contained diving where gas is exhaled directly to the surroundings
  - Rebreather diving – Underwater diving using self contained breathing gas recycling apparatus
- Surface-supplied diving – Underwater diving breathing gas supplied from the surface
  - Surface oriented diving – Underwater diving in which the diver starts and finishes at surface pressure
    - Air-line diving – Basic mode of surface-supplied underwater diving
    - Hookah diving – Underwater diving using a basic air hose from the surface
    - Bell bounce diving, also known as transfer under pressure diving – Surface oriented diving using a closed bell
    - Compressor diving – Crude mode of surface-suplied air diving
  - Saturation diving – Diving decompression technique
Atmospheric pressure diving – Diving in an articulated pressure resistant anthropomorphic housing
Unmanned diving – Underwater diving by autonomous or remotely operated vehicles

Diving skills and procedures

Divers decompressing in the water at the end of a dive

Divers doing a buddy check

Sidemount diver pushing a cylinder in front

Solo diver surveying dive site. The bailout cylinder can be seen slung at the diver's left side.

Diving procedures – Standardised methods of doing things that are known to work effectively and acceptably safely

Ascending and descending (diving) – Procedures for safe ascent and descent in underwater diving
- Ear clearing – Equalising of pressure in the middle ears
- Emergency ascent – An ascent to the surface by a diver in an emergency
  - Controlled emergency swimming ascent – Emergency procedure for scuba divers when out of air
  - Controlled buoyant lift – A technique used by scuba divers to raise an incapacitated diver to the surface
Bell bounce diving – Surface oriented diving using a closed bell
Boat diving – Procedures specific to diving from boats
- Canoe and kayak diving – Recreational diving from a canoe or kayak
Buoyancy control in scuba diving – Essential safety skill
Decompression (diving) – Pressure reduction and its effects during ascent from depth
- Decompression practice – Techniques and procedures for safe decompression of divers
  - Accelerated decompression – Decompresssion using oxygen-rich breathing gases
  - Altitude decompression – Reduction in ambient pressure due to ascent above sea level
  - Continuous decompression – Decompression without specific stops at given depths
  - Cross altitude corrections – Adjustments to the US Navy decompression tables to allow for altitude
  - Decompression stop – Pause during tascent from a dive to release dissolved inert gas in tissues
  - Deep stop – Additional stop deeper than the first obligatory decompression stop
  - Flying after diving, also known as ascent to altitude after diving – Precautions against decompression sickness when ascending to altitude after diving
  - Gas switching – Changing the breathing gas mixture during a dive
  - Pyle stop – Type of short deep decompression stops in addition to the standard profile
  - Ratio decompression – Rule of thumb for estimating a decompression schedule for a given set of breathing gases
  - Residual nitrogen time – Estimate of excess nitrogen remaining in tissues before repetitive dive
  - Safety stop – Optional decompression stop to reduce decompression stress
  - Saturation decompression – Decompression where all tissues are saturated with inert gas
  - Stage decompression – Decompression during ascent based on decompression stops
  - Surface decompression – Decompression in a diving chamber out of the water
Dive log – Record of diving history of an underwater diver
Dive planning – The process of planning an underwater diving operation
Diver communications – Methods used by underwater divers to communicate
Diver navigation – Underwater navigation by scuba divers
Diver rescue – Rescue of a distressed or incapacitated diver
Diver trim – Balance and orientation skills of an underwater diver
Diving heavy – Underwater diving while intentionally negatively buoyant
Drift diving – Scuba diving where the diver is intentionally transported by the water flow
Finning techniques – Techniques used by divers and surface swimmers using swimfins
- Back kick (finning) – Finning technique to move backwards
- Combat sidestroke – Variation of side-stroke swimming used by United States Navy SEALs
- Dolphin kick – Swimming style
- Flutter kick – Kicking movement used in both swimming and calisthenics
- Frog kick – Finning propulsion kick used particularly by cave and wreck divers
- Helicopter turn – Rotation about a vertical axis by an underwater diver using only fins
- Scissor kick (finning) – Techniques used by divers and surface swimmers using swimfins
Repetitive dives – Diving again before the dissolved nitrogen has fully equilibrated
- Surface interval – The time spent out of the water between dives
Scuba skills – The skills required to dive safely using a self-contained underwater breathing apparatus.
- Buddy breathing – Technique for sharing breathing gas from a single mouthpiece
- Buddy diving – Practice of mutual monitoring and assistance between two divers
  - Buddy check – Pre-dive safety checks carried out by two-diver dive teams
- Low impact diving – Scuba diving that has minimal environmental effect
- Penetration diving – Diving under a physical barrier to a direct vertical ascent to the surface
- Rebreather diving – Underwater diving using self contained breathing gas recycling apparatus
- Scuba gas management – Logistical aspects of scuba breathing gas
  - Gas blending for scuba diving – Mixing and filling cylinders with breathing gases for use when scuba diving
  - Rule of thirds (diving) – Rule of thumb for scuba gas management
  - Scuba gas planning – Estimation of breathing gas mixtures and quantities required for a planned dive profile
- Sidemount diving – Diving using equipment configuration where scuba sets are clipped to the diver's sides
- Solo diving – Recreational diving without a dive buddy
Saturation diving – Diving decompression technique
- Saturation decompression – Decompression where all tissues are saturated with inert gas
- Transfer under pressure – Moving between pressurised vessels without decompression
- Lock-in (diving) – Enter an enclosed environment at a different pressure to ambient through an air-lock
- Lock-off – Split a secure airtight connection between two pressurised chambers via an airlock
- Lock-on (diving) – Make a secure airtight connection between two pressurised chambers via an airlock
- Lock-out (diving) – Exit an enclosed environment at a different pressure to ambient through an air-lock
Surface-supplied diving skills – Skills and procedures required for the safe operation and use of surface-supplied diving equipment
- Umbilical management – Safe handling of the diver's umbilical
Underwater searches – Techniques for finding underwater targets

Diving support skills and procedures

Diving gas analysis – Measuring the components in a breathing gas blend
- Electro-galvanic oxygen sensor – Electrochemical device for measuring oxygen partial pressure
- Helium analyser – Instrument to measure the concentration of helium in a gas mixture
Gas blending – Producing special gas mixtures to specification
- Gas blending for scuba diving – Mixing and filling cylinders with breathing gases for use when scuba diving
  - Partial pressure blending – Gas blending based on pressure ratio of components
  - Mass fraction blending – Mixing gas by measuring added mass of each component
  - Continuous blending and compression – Gas blending by constant flow mixing and analysis
  - Air top-up, also known as Air top – Modifying or completing a gas blend by adding compressed air
- Oxygen compatibility – Usability in high-oxygen environments
Chamber operation, also known as decompression chamber operation and diving chamber operation – Operation of a hyperbaric chamber in support of underwater diving
Dive boat operation – Operational procedures for a boat supporting diving
Dive supervision, also known as diver supervision and monitoring – The work of the manager of a professional diving team
Diving bell deployment – Deployment of a modern diving bell
Diving equipment maintenance and testing – Ensuring that the equipment is safe to use
Diving project – The overall diving job by a diving contractor under a specific contract
Diving project management
Diving project mobilisation and demobilisation
Diving stage deployment – Launch and recovery of a diving stage
Hazmat diving decontamination – Removing hazardous environmental contaminants from the diver after a dive
Job safety analysis – Procedure to integrate safety practices into a particular task
Life support system operation – Operation of the systems which are necessary for the survival of the occupants
Risk assessment – Estimation of risk associated with exposure to a given set of hazards
ROV operation
Surface stand-by diver procedures – Functions of member of a professional diving team
Surface-supplied gas management – Provision of breathing gas to surface-supplied divers
Umbilical tending – Management of the supply end of the diver's umbilical

Underwater diving, by environment

Ice Diving – View from the top

Underwater diving environment – The underwater environment to which a diver may be exposed

List of diving environments by type – Variety of environments that people may dive in
Open-water diving – Diving with access to breathable air of the atmospher
Altitude diving – Underwater diving at altitudes above 300 m
Cave diving – Diving in water-filled caves
Deep diving – Underwater diving to a depth beyond the norm accepted by the associated community
Ice diving – Underwater diving under ice
Muck diving – Recreational diving on a loose sedimentary bottom
Night diving – Underwater diving during the hours of darkness
Recreational dive sites – Places that divers go to enjoy the underwater environment
Underwater environment – Aquatic or submarine environment
Wreck diving – Recreational diving on wrecks

Occupational diving

Underwater welding.

NAUI Nitrox diver certification card

Pearl diver in Japan

Nesconset fire department scuba rescue team on training exercise

Salvaging a ship's propeller

A diver at work on hull maintenance

Sponge diver putting on his diving suit in Tarpon Springs, Florida.

Professional diving, also known as occupational diving – Underwater diving where divers are paid for their work

Ama – Japanese pearl divers
Aquarium diving – Occupational diving in large aquariums
Commercial diving – Professional diving on industrial projects
- Commercial offshore diving – Professional diving in support of the oil and gas industry
- Hyperbaric welding – Welding metal at elevated pressure
- Nondestructive testing – Evaluating the properties of a material, component, or system without causing damage
Dive leader – Recreational diving certification and role
Diver training – Processes to develop the skills and knowledge to dive safely underwater
- Diving instructor – Person who trains and assesses underwater divers
- Diving school – Establishment for training and assessing underwater divers
- Occupational diver training – Training of people employed as underwater divers
  - Commercial diver training – Processes by which people learn to dive safely for industrial applications
  - Military diver training – Training of underwater divers for service in the armed forces
  - Public safety diver training – Training divers for public safety services
  - Scientific diver training – Training divers who will be doing scientific work underwater
- Recreational diver training – Training process for people who do not dive at work
  - Technical diver training – Processes to develop skills and knowledge to dive safely for technical diving
- Diver certification – Certification as competent to dive to a specified standard
  - List of diver certification organizations – Agencies which issue certification for competence in diving skills
- Diamond Reef System – System for training divers in buoyancy, trim and maneuvering skills
Divemaster, also known as dive guide, or dive leader – Recreational dive leader certification and role
Diving contractor – The legal persona responsible for professional diving operations for a client
Haenyeo – Female divers of Jeju, South Korea
Hazmat diving – Underwater diving in a known hazardous materials environment
Media diving – Underwater diving in support of the media industries
Military diving – Underwater diving in a military context by members of an armed force
- Defense against swimmer incursions – Methods of protection from incursions by divers and swimmers
- Army engineer diver – Armed forces occupation
- Clearance diver – Navy diver specialist with explosives
- List of military diving units
  - Army Ranger Wing – Special operations force of the Irish Defence Forces
  - British commando frogmen – Special Boat Service, whose members are drawn largely from the Royal Marines
  - Canadian Armed Forces Divers – Underwater divers employed by any of the Canadian armed forces
  - Clearance Diving Branch (RAN) – Diving unit of the Royal Australian Navy
  - Comando Raggruppamento Subacquei e Incursori Teseo Tesei – Italian special forces diving unit
  - Commandos Marine – Special operations forces of the French Navy
  - Commandos Marine § Commando Hubert – Special operations forces of the French Navy – Unit with combat swimmers.
  - Decima Flottiglia MAS – Italian naval commando frogman unit of the Fascist era
  - Frogman – Tactical scuba diver
  - GRUMEC, also known as Brazilian commando frogmen – Brazilian Navy special forces diving unit
  - Kommando Spezialkräfte Marine – German postwar commando amphibious warfare force
  - KOPASKA – Indonesian Navy special operations and demolition unit
  - Marine Commandos – Marine special operations group of the Lebanese Army
  - Minedykkerkommandoen – Norwegian Navy clearance diver unit
  - Minentaucher – Mine clearance divers of the German Navy
  - PASKAL – Special operations force of the Royal Malaysian Navy
  - Naval Service Diving Section – Diving unit of the Irish Naval Service
  - Naval Special Warfare Command (Thailand) – Special operations force within the Military of Thailand
  - Röjdykare – Clearance divers of the Swedish Navy
  - Russian commando frogmen – Tactical scuba diving unit
  - Shayetet 13 – Special operations unit of the Israeli Navy
  - Special Boat Service – Special forces unit of the Royal Navy
  - Special Service Group – Special operations force of the Pakistan Navy
  - Taifib – Indonesian amphibious reconnaissance unit
  - Underwater Defence – Special operations unit of the Turkish Navy
  - Underwater Demolition Command – Special warfare unit of the Greek Navy
  - Underwater Offence – Special operations Forces of the Turkish Navy
  - United States military divers – Underwater divers employed by the US armed forces
    - Master diver – Senior diver rating in US Navy
    - Navy diver – US Navy personnel qualified in underwater diving and salvage
    - Explosive ordnance disposal – US Navy personnel who render safe or detonate unexploded ordnance
    - Underwater Demolition Team – US Navy special operations group
    - United States Marine Corps Combatant Diver Course – Military diver training for the US Marines
    - United States Navy SEALs – U.S. Navy special operations force
      - List of United States Navy SEALs – Notable members of the US Navy SEALs and UDTs
      - United States Navy SEAL selection and training – Special forces unit policy and procedures
      - National Navy UDT-SEAL Museum – Museum of US Navy special forces units
- Underwater warfare – One of the three operational areas of naval warfare
Nuclear diving – Diving in an environment where there is a risk of exposure to radioactive materials
Pearl hunting – Collecting pearls from wild molluscs
Public safety diving – Underwater work done by law enforcement, rescue and search and recovery teams
- Police diving – A branch of professional diving carried out by police services
  - Special Duties Unit – Hong Kong Police tactical unit
Salvage diving – Diving work associated with the recovery of vehicles, cargo and structures
Scientific diving – Use of diving techniques in the pursuit of scientific knowledge
Ships husbandry diving – Diving related to the maintenance and upkeep of ships
Sponge diving – Diving to gather natural sponges
Underwater archaeology – Archaeological techniques practiced at underwater sites
Underwater demolition – The deliberate destruction or neutralization of man-made or natural underwater obstacles
Underwater photography – Genre of photography
Underwater search and recovery – Locating and recovering underwater objects
Underwater videography – Electronic underwater photography concerned with capturing moving images

Recreational diving

Diver returning from a 600 ft (183 m) technical dive

Two underwater hockey players competing for the puck

Underwater photographer

Divers on the wreck of the Zenobia

Recreational diving – Diving for the purpose of leisure and enjoyment, usually when using scuba equipment

Technical diving – Extended scope recreational diving
- Cave diving – Diving in water-filled caves
- Doing It Right – Technical diving safety philosophy
Shark tourism – Tourism industry based on viewing wild sharks
- Shark cage diving – Diving inside a protective cage to observe sharks in the wild
  - Shark-proof cage – A metal structure to protect divers and snorkellers from potentially dangerous sharks
  - Shark baiting – Attracting sharks by chumming the water
Underwater photography – Genre of photography
Underwater sports – Competitive underwater recreational activities
- Aquathlon – Competitive underwater wrestling
- Competitive apnea – Competitive breathhold diving
  - Constant weight apnea – Freediving discipline
  - Constant weight without fins – Freediving discipline
  - Dynamic apnea – Freediving disciplines where the diver swims horizontally under water
  - Free immersion apnea – Human-powered freediving discipline
  - No-limits apnea – Freediving discipline in which the diver descends and ascends using their method of choice
  - Variable weight apnea – Deep freediving using a weighted sled for descent, pulling along the depth rope for ascent
  - Static apnea – Stationary diving discipline of holding breath underwater
  - Skandalopetra diving – Freediving using a stone weight at the end of a rope to the surface
- Finswimming – Competitive watersport using swimfins for propulsion
  - 2016 Finswimming World Championships – International competition in Volos, Greece
  - 2018 Finswimming World Championships – International competition in Belgrade, Serbia
  - Apnea finswimming – Underwater swimming in a swimming pool using mask, monofin and holding one's breath.
  - Finswimming at the 2009 Asian Indoor Games – Competition held in Mỹ Đình National Aquatics Sports Complex, Hanoi, Vietnam
  - Immersion finswimming – Competitive scuba watersport using swimfins for propulsion
- Spearfishing – Hunting for fish using a spear
- Sport diving – Underwater sport using recreational open circuit scuba equipment in a swimming pool
- Underwater football – Underwater team sport using snorkeling equipment and an American football
- Underwater hockey – Underwater sport of pushing a puck into the opposing goal
- Underwater ice hockey – Freediving variant of ice hockey played upside-down under the ice
- Underwater orienteering – Underwater compass navigation and speed competition on scuba.
- Underwater photography – Competitive underwater digital photography on scuba
- Underwater rugby – Underwater team sport
- Underwater target shooting – Breathhold underwater sport of target shooting with a speargun in a swimming pool.
Wreck diving – Recreational diving on wrecks

Diving and support equipment, tools and weapons

Small high-pressure breathing air compressor

A small scuba filling and blending station supplied by a compressor and storage bank

Three representative wrist-mount dive computers

International code flag Alpha indicates that a diver is underwater nearby

A closed bell used for saturation diving

Lifting bag used to move a heavy object underwater

The Newtsuit atmospheric diving suit

US Navy Diver using Kirby Morgan 37 diving helmet

Helmeted diver entering the water. He has a back mounted Draeger DM40 rebreather system in addition to the surface supply air hose

Scuba diver with bifocal lenses in half mask

A diver wearing an Ocean Reef full face mask

U.S. Navy divers in dry suits prepare to dive

Two men operating a rotary diver's air pump

Diving equipment

Diving equipment – Equipment used to facilitate underwater diving

Autonomous underwater vehicle – Uncrewed underwater vehicle with autonomous guidance system
Breathing gas – Gas used for human respiration
Buoyancy control device – Equipment for controlling the buoyancy of a diver
Decompression equipment – Equipment used by divers to facilitate decompression
Dive light – Light used underwater by a diver
Diver propulsion vehicle – Powered device for diver mobility and range extension
Diving bell – Chamber for transporting divers vertically through the water
- Dry bell, also known as closed bell – Hyperbaric chamber for transporting diversvertically through the water
- Wet bell, also known as open bell – Platform for transporting divers vertically through the water
Diving mask – Watertight air-filled face cover with view-ports for improving underwater vision
- Anti-fog – Chemicals that prevent the condensation of water as small droplets on a surface
- Full-face diving mask – Diving mask that covers the mouth as well as the eyes and nose
- Integrated Diver Display Mask – Diving half-mask with integrated head-up instrument display
Diving safety equipment – Equipment used to facilitate underwater diving safety
Diving suit – Garment or device designed to protect a diver from the underwater environment
- Atmospheric diving suit – Articulated pressure resistant anthropomorphic housing for an underwater diver
- Dry suit – Watertight clothing that seals the wearer from cold and hazardous liquids
- Hot water suit – A wetsuit with a supply of heated water to keep a diver warm
- Rash guard, also known as rash vest – Stretch garment for protection from abrasion, UV and stings
- Wetsuit – Garment worn to provide thermal protection while wet
- Standard diving dress – Copper helmet with rubberised canvas diving suit and weighted boots
Diving weighting system – Ballast carried to counteract buoyancy
- Ankle weights (diving) – Diver trim weights worn at the ankles
- Clip-on weight – Small weights used to make fine adjustments to a diver's ballast
- Clump weight – A heavy weight suspended on cable used to guide a diving bell
- Helmet weight – Ballast added to a diving helmet to prevent it from floating
- Integrated weights, also known as BCD integrated weights, or pocket weights – Diving weights carried in pockets on the buoyancy compensator
- Keel weight (diving) – Weight added to a diver's backplate
- Tank weight, also known as cylinder weight – Ballast weight attached to a scuba cylinder
- Trim weights (diving) – Diving weights distributed primarily to improve trim
- Weight belt – Ballast carried to counteract buoyancy
- Weight pocket – Container on diving equipment to hold ballast
- Weighted shoes (diving), also known as Weighted boots (diving) – Shoes with heavy metal soles used as part of a diver's weights
- Weight harness – Webbing system to support diver ballast weights
- Diving weight – Ballast carried by a diver to counteract buoyancy or adjust trim
Remotely operated underwater vehicle – A tethered underwater mobile device operated by a remote crew
Snorkel – Tube for breathing face down at the surface of the water
Swimfin – Finlike accessories worn on the feet, used for swimming, snorkeling and diving propulsion
- Monofin – Single blade swimfin attached to both feet
Towboard – Underwater survey equipment used to tow a diver
Underwater breathing apparatus – Equipment which provides breathing gas to an underwater diver
- Scuba set – Self-contained underwater breathing apparatus
  - Diving cylinder – Container to supply high pressure breathing gas for divers
  - Diving regulator – Mechanism that controls the pressure of a breathing gas supply for diving
  - Rebreather – Portable apparatus to recycle breathing gas
- Surface-supplied diving equipment – Equipment used specifically for surface supplied diving
  - Diving helmet – Rigid head enclosure for underwater diving
  - Diver's umbilical – Hose supplying breathing gas to a diver from the support platform
Atmospheric diving suit (ADS) – Articulated pressure resistant anthropomorphic housing for an underwater diver
Crewed submersible – Small watercraft able to navigate under water

Autonomous underwater vehicles

Autonomous underwater vehicle – Uncrewed underwater vehicle with autonomous guidance system

Autonomous Robotics Ltd – UK company developing an autonomous underwater vehicle
AUV-150 – Unmanned underwater vehicle in development in by Central Mechanical Engineering Research Institute
AUV Abyss – Autonomous underwater vehicle for mapping of the seabed and water column data collection
Boaty McBoatface – British autonomous underwater vehicle
DeepC – Autonomous underwater vehicle powered by a fuel cell
DEPTHX – Autonomous underwater vehicle for exploring sinkholes in Mexico
Echo Ranger – Marine autonomous underwater vehicle built by Boeing
Eelume – Autonomous underwater vehicle being developed by Eelume AS
Explorer AUV – Autonomous underwater vehicle from People's Republic of China
Intelligent Water class AUV – Autonomous underwater vehicle for the People's Liberation Army Navy
Intervention AUV – Type of autonomous underwater vehicle capable of autonomous interventions
iRobot Seaglider – Deep diving autonomous underwater vehicle for long term missions
Maya AUV India – Autonomous underwater vehicle from National Institute of Oceanography, India
Nereus (underwater vehicle) – Hybrid remotely operated or autonomous underwater vehicle
REMUS (AUV) – Autonomous underwater vehicle series
Sentry (AUV) – Autonomous underwater vehicle made by Woods Hole Oceanographic institution
Spindle (vehicle) – Ice penetrating two-stage autonomous underwater vehicle
SPURV – Self propelled underwater research vehicle built in 1957 for the US Navy
SPURV II – Special purpose underwater research vessel built to srudy submarine wakes
Theseus (AUV) – Large autonomous underwater vehicle for laying fibre-optic cable

Breathing gas

Breathing gas – Gas used for human respiration

Breathing gases by composition:
- Argox – Gas mixture occasionally used by scuba divers for dry-suit inflation
- Breathing air – Air quality suitable for safe breathing
- Heliox – A breathing gas mixed from helium and oxygen
- Hydreliox – Breathing gas mixture of hydrogen, helium, and oxygen
- Hydrox (breathing gas) – Breathing gas mixture experimentally used for very deep diving
- Nitrox – Breathing gas, mixture of nitrogen and oxygen
- Oxygen – Chemical element with symbol O and atomic number 8
- Trimix (breathing gas) – Breathing gas consisting of oxygen, helium and nitrogen
Breathing gases by use:
- Bailout gas – Emergency breathing gas supply carried by the diver
- Bottom gas – Gas breathed during the deep part of a dive
- Decompression gas – Oxygen-rich gas used for accelerated decompression
- Emergency gas supply – Alternative independent breathing gas supply carried by a diver
- Travel gas – Gas breathed during the descent part of a dive

Decompression equipment

Decompression equipment – Equipment used by divers to facilitate decompression

Airlock – Compartment for transfer between environments with different atmospheres
Bottom timer, also known as dive timer – An electronic instrument that records depth and elapsed time data on an underwater dive
Deck decompression chamber, also known as decompression chamber – Hyperbaric chamber suitable for surface decompression or emergency use at a dive site
Decompression buoy – Inflatable surface marker buoy deployed from underwater
Decompression cylinder – Scuba cylinder carrying decompression gas
Decompression gas – Oxygen-rich gas used for accelerated decompression
Decompression trapeze – Horizontal bars suspended at decompression stop depths
Depth gauge – Instrument that indicates depth below a reference surface
Dive computer, also known as decompression computer – Instrument to calculate decompression status in real time
Dive tables, also known as decompression tables, decompression schedules – Data used to determine a decompression schedule for a given dive profile and breathing gas
Diving bell – Chamber for transporting divers vertically through the water
- Closed bell, also known as dry bell – Hyperbaric chamber for transporting divers vertically through the water
- Wet bell, also known as open bell – Platform for transporting divers vertically through the water
Diving chamber – Hyperbaric pressure vessel for human occupation used in diving operations
Diving shot, also known as Shot line – Substantial weighted near-vertical line with buoy
Diving stage, also known as diving basket – Platform on which a diver is transported vertically through the water
Jonline – A short line used by scuba divers to clip themselves to something
Pneumofathometer – Instrument for measuring the depth of a diver by air pressure
Recreational Dive Planner – PADI no-decompression dive table also available as a circular slide rule and electronic calculator
Saturation system – Diving decompression system

Diver propulsion vehicles

Diver propulsion vehicle – Powered device for diver mobility and range extension

Advanced SEAL Delivery System – Former Navy SEAL mini-sub deployed from submarines
Shallow Water Combat Submersible – Manned submersible and a type of swimmer delivery vehicle
Wet sub – Ambient pressure diver propulsion vehicle
- Cosmos CE2F series – Italian swimmer delivery vehicles
- Human torpedo – Early form of diver propulsion vehicle
- Motorised Submersible Canoe – WWII British frogman delivery vehicle
- Necker Nymph – DeepFlight Merlin class positively-buoyant open-cockpit 3-seater wet sub
- R-2 Mala-class swimmer delivery vehicle – 2-man wet sub swimmer delivery vehicle class of the Yugoslavian, and later, Croatian, Navies
- SEAL Delivery Vehicle – Manned wet submersible for deploying naval special forces
- Siluro San Bartolomeo – Italian manned torpedo design of late WWII
- Wet Nellie – 1976 car-shaped submarine from the James Bond film The Spy Who Loved Me

Diving safety equipment

Diving safety equipment – Equipment used to facilitate underwater diving safety

Adjustable buoyancy life jacket (ABLJ) – Chest inflation type buoyancy compensator
Alternative air source – Emergency supply of breathing gas for an underwater diver
AR vest, also known as Arvest and R vest – Type of jacket harness for surface-supplied diving
Bailout cylinder, also known as bailout bottle – Emergency gas supply cylinder carried by a diver
Buddy line – A tether between two scuba divers to prevent separation in low visibility
Buoyancy compensator (diving) (BC, BCD), also known as buoyancy control device – Equipment for controlling the buoyancy of a diver
Decompression equipment – Equipment used by divers to facilitate decompression
- Decompression buoy (DSMB), also known as Delayed surface marker buoy – Inflatable surface marker buoy deployed from underwater
- Decompression trapeze – Horizontal bars suspended at decompression stop depths
Distance line, also known as dive reel or guide line – Line deployed by scuba divers for navigation
Diver surface detection aids – Equipment to make a surfaced diver easier to find
Diver's cutting tool – A tool to assist in extricating the diver from entrapment by lines or nets
Diver's knife – A tool to assist in extricating the diver from entrapment by lines or nets
Diving safety harness, also known as bell harness – A harness by which the diver can safely be lifted
Jonline – A short line used by scuba divers to clip themselves to something
Jacket harness – Type of surface-supplied diving safety harness
Jump jacket – Surface-supplied diving safety harness with buoyancy compensation
Lifeline, also known as tether – A rope connecting the diver to an attendant, usually at the surface
Line marker – Marker used on cave guide lines to provide safety information to divers
Rescue tether – Equipment to facilitate a diver rescue
Shotline – Substantial weighted near-vertical line with buoy
Safety sausage – Inflatable buoy used by a diver at the surface to indicate position to the dive boat
Surface marker buoy – Buoy towed by a scuba diver to indicate the diver's position

Historical diving equipment

Motorised Submersible Canoe – WWII British frogman delivery vehicle
Necker Nymph – DeepFlight Merlin class positively-buoyant open-cockpit 3-seater wet sub
R-2 Mala-class swimmer delivery vehicle – 2-man wet sub swimmer delivery vehicle class of the Yugoslavian, and later, Croatian, Navies
Siluro San Bartolomeo – Italian manned torpedo design of late WWII
Standard diving dress – Copper helmet with rubberised canvas diving suit and weighted boots
Sub Marine Explorer – Early submarine craft
Wet Nellie – 1976 car-shaped submarine from the James Bond film The Spy Who Loved Me

Rebreather types and components

Diving rebreather – Closed or semi-closed circuit scuba

Bailout valve (rebreather) (BoV), also known as Rebreather bailout valve – Valve on rebreather mouthpiece to switch to emergency gas supply
Carbon dioxide scrubber – Device which absorbs carbon dioxide from circulated gas
Counterlung – Volume compensating device in a rebreather
Closed circuit bailout – Emergency gas supply from an independent closed circuit rebreather
Closed circuit rebreather – Breathing apparatus that recirculated breathing gas
- Elecrtonically controlled closed circuit rebreather (ECCCR) – Underwater breathing apparatus
- Manually controlled closed circuit rebreather (MCCCR) – Rebreather in which the oxygen content of the loop gas is controlled by the diver
Cryogenic rebreather – Rebreather that removes CO2 by freezing it out using heat exchange with liquid oxygen
Dive/surface valve – Valve on a rebreather mouthpiece to isolate the breathing loop when not in use
Gas extender – Type of semi-closed circuit diving rebreather
Head-up display (HUD) – Transparent display presenting data within normal sight lines of the user
- Rebreather head-up display – User information interface always in view of the diver
Loop rebreather – Rebreather architecture with one-way flow
Mixed gas rebreather – Rebreather using gas other than only oxygen
Oxygen rebreather – Rebreather using pure oxygen as the breathing gas
Pendulum rebreather – Configuration using biderctional gas flow
Semi-closed rebreather – Rebreather that replenishes oxygen by continuously adding a gas mixture
- Active addition semi-closed circuit rebreather – Adds feed gas to the breathing circuit and excess gas is dumped
- Passive addition semi-closed circuit rebreather – Dumps gas from the breathing circuit and makes up volume on demand

Rebreather makes and models

Carleton CDBA – Military rebreather by Cobham plc
Clearance Divers Life Support Equipment – British military electronically controlled closed circuit rebreather
Cis-Lunar – Manufacturer of electronically controlled closed-circuit rebreathers for scuba diving
CUMA – Canadian military diving rebreather
Davis Submerged Escape Apparatus – Early submarine escape oxygen rebreather also used for shallow water diving.
Dräger Dolphin – Semi-closed circuit recreational diving rebreather
Dräger Ray – Semi-closed circuit diving rebreather
FROGS – Closed circuit oxygen diving rebreather
Halcyon RB80 – Non-depth-compensated passive addition semi-closed circuit rebreather
Halcyon PVR-BASC – Semi-closed circuit depth compensated passive addition diving rebreather
IDA71 – Russian military rebreather for underwater and high altitude use
Interspiro DCSC – Military semi-closed circuit passive addition diving rebreather
KISS – Manual closed circuit mixed gas rebreather
LAR-5, LAR-6, and LAR-V represented by Dräger (company) – German manufacturer of breathing equipment
Lambertsen Amphibious Respiratory Unit – Early closed circuit oxygen diving rebreather
Porpoise – Australian scuba manufacturer
Siebe Gorman CDBA – Type of diving rebreather used by the Royal Navy
Siva – Range of military rebreathers
Viper – Electronically-controlled closed circuit mixed gas military rebreather

Gas extenders:

Mk V Mod 1 Heliox helmet – US Navy standard diving helmet modified for heliox
- Hoke valve – Gas recirculation control valve on MK V helium hemet
Morse Engineering Mk 12 helmet – US Navy deep water free-flow helmet
Dräger Modell 1915 Bubikopf helmet – Copper helmet for rebreather systems
- Dräger DM20 oxygen rebreather system – Oxygen rebreather system for copper helmet
- Dräger DM40 mixed gas rebreather system – Nitrox rebreather system for copper helmet

Remotely operated underwater vehicles

Remotely operated underwater vehicle – A tethered underwater mobile device operated by a remote crew

8A4-class ROUV – Chinese work class remotely operated underwater vehicle
ABISMO – Japanese remotely operated underwater vehicle for deep sea exploration
Atlantis ROV Team – High-school underwater robotics team from Whidbey Island, Washington, United States
CURV – Early remotely operated underwater vehicle
Épaulard – French remotely operated underwater vehicle of the Ifremer
Global Explorer ROV – Deep water science and survey remotely operated vehicle
Goldfish-class ROUV – Light class of Chinese remotely operated underwater vehicle
Kaikō ROV – Japanese remotely operated underwater vehicle for deep sea exploration
Long-Term Mine Reconnaissance System – American torpedo tube-launched underwater search and survey unmanned undersea vehicle
Mini Rover ROV – Small, low cost observation class remotely operated underwater vehicle
OpenROV – Open-source remotely operated underwater vehicle
ROV KIEL 6000 – Remotely operated vehicle built by Schilling Robotics, Davis, California for scientific tasks
ROV PHOCA – Remotely operated underwater vehicle of the COMANCHE type
Scorpio ROV – Work class remotely operated underwater vehicle
Sea Dragon-class ROV – Chinese deep diving work class remotely operated underwater vehicle
Seabed tractor – Special purpose class of remotely operated underwater vehicle
Seafox drone – Remotely operated anti-mine marine drone
SeaPerch – Remotely operated underwater vehicle educational program
SJT-class ROUV – Series of Chinese remotely operated underwater vehicles
T1200 Trenching Unit – Remotely operated seabed trenching unit
VideoRay UROVs – Series of inspection class remotely operated underwater vehicles

Underwater breathing apparatus

Underwater breathing apparatus – Equipment which provides breathing gas to an underwater diver

Scuba set – Self-contained underwater breathing apparatus
- Alternative air source – Emergency supply of breathing gas for an underwater diver
  - Bailout bottle, also known as bailout cylinder – Emergency gas supply cylinder carried by a diver
  - Emergency gas supply – Alternative independent breathing gas supply carried by a diver
  - Helicopter Aircrew Breathing Device – Small scuba device for escape from ditched helicopters
  - Pony bottle – Small independent scuba cylinder usually carried for emergency gas supply
  - Submarine escape set – Self contained breathing apparatus providing gas to escape from a submerged submarine
- Backplate and wing – Type of back-mount scuba harness
- Diving cylinder – Container to supply high pressure breathing gas for divers
  - Burst disc – Non-closing over-pressure relief device
  - Cylinder valve alias Pillar valve represented by Diving cylinder#The cylinder valve – A valve to control gas flow to and from a cylinder and to connect with the regulator or filling hose
  - Hydrostatic test – Non-destructive test of pressure vessels
  - Sustained load cracking – Metallurgical failure mode of cracking under a prolonged static load
  - Testing and inspection of diving cylinders – Periodical inspection and testing to revalidate fitness for service
- Diving regulator – Mechanism that controls the pressure of a breathing gas supply for diving
  - Breathing performance of regulators – Capacity of breathing regulators to function as specified
- Rebreather – Portable apparatus to recycle breathing gas
- Scuba manifold – Scuba component used to functionally connect diving cylinders
- Sidemount diving – Diving using equipment configuration where scuba sets are clipped to the diver's sides
Surface-supplied diving equipment – Equipment used specifically for surface supplied diving
- Air line, also known as air-line – Tube or hose carrying a compressed air supply
- Bailout cylinder – Emergency gas supply cylinder carried by a diver
- Bailout block – Valve block on diver's equipment for switching between main and emergency gas supply
- Diving helmet – Rigid head enclosure for underwater diving
- Diver's umbilical – Hose supplying breathing gas to a diver from the support platform
- Diving stage – Platform on which a diver is transported vertically through the water
- Gas panel – Breathing gas distribution panel for surface-supplied diving
- Pneumofathometer – Instrument for measuring the depth of a diver by air pressure
- Snuba – Limited depth airline breathing apparatus towed by the diver
- Standard diving dress – Copper helmet with rubberised canvas diving suit and weighted boots

Diving support equipment

Diving support equipment – Equipment used in the support of an underwater diving operation

Booster pump – Machine to increase pressure of a fluid
Cascade filling system – Filling pressurized gas from a series of storage cylinders
Communications panel, also known as Diver's telephone – Surface control panel for underwater diving voice communications system
Diver down flag – Flag signal indicating divers are in the water nearby
Diver lock-out submersible – Manned submersible with an airlock for underwater use
Diver's pump, also known as Diver's air pump – Manually powered surface air supply for divers
Diving air compressor, also known as Diving compressor – Machine used to compress breathing air for use by underwater divers
Diving chamber – Hyperbaric pressure vessel for human occupation used in diving operations
- Hyperbaric stretcher – Portable pressure vessel to transport a person under pressure.
Diving spread – The topside base for commercial diving operations
- Air spread – The topside base for surface-supplied air diving operations
- Saturation spread – The topside base for saturation diving operations
  - Saturation system – Diving decompression system
Diving support vessel – Ship used as a floating base for professional diving projects
- HMS Challenger – Royal Navy saturation diving support vessel
- Liveaboard – Way of using a boat
- Dive boat – Boat used for the support of scuba diving operations
  - Combat Rubber Raiding Craft – Rubberised fabric tactical inflatable boat used by the US Navy
- Diving ladder – Ladder to facilitate egress from the water by divers
- Diving platform (scuba) – Low freeboard platform on a dive boat to give divers easy access to the water
- Moon pool – Opening in the base of a hull, platform, or chamber giving access to the water below
Echo sounder, also known as fish finder – Measuring the depth of water by transmitting sound waves into water and timing the return
Gas panel, also known as Diving gas distribution manifold – Breathing gas distribution panel for surface-supplied diving
Helium analyzer – Instrument to measure the concentration of helium in a gas mixture
Helium reclaim system – System for recovering exhaled breathing gas
Launch and recovery system (LARS) – Equipment used to deploy and recover a diving bell, stage, or ROV
Marine VHF radio – Radios operating in the very high frequency maritime mobile band
Nitrox production – Methods of producing nitrox mixtures
- Membrane gas separation – Technology for splitting specific gases out of mixtures
- Pressure swing adsorption – Method of gases separation using selective adsorption under pressure
Proton magnetometer, also known as metal detector – Instrument which measures very small variations in the Earth's magnetic field
Recreational Dive Planner (RDP) – PADI no-decompression dive table also available as a circular slide rule and electronic calculator
Remotely operated underwater vehicle (ROV) – A tethered underwater mobile device operated by a remote crew
Satellite navigation – Use of satellite signals for geo-spatial positioning
- Global Positioning System (GPS) – American satellite-based radio navigation service
Subsurface (software) – Open source software for logging and planning scuba dives
Trongle – Device used on submarines to help swimmers to locate a submerged submarine

Underwater work tools and equipment

Soviet SPP-1 underwater pistol

Airlift dredging

ROV at work in an underwater oil and gas field. The ROV is operating a subsea torque tool (wrench) on a valve on the subsea structure.

Underwater work tools and equipment – Tools and equipment used for underwater work

Airlift (dredging device) – Dredging device using injected air to move water and entrained load up a pipe
High-pressure water jetting – Cleaning method using very high pressure water jet
Lifting bag – Airtight bag used for underwater buoyant lifting when filled with air
Remotely operated underwater vehicle – A tethered underwater mobile device operated by a remote crew
Snoopy loop – Rubber band made from inner tube
Tremie – Equipment for underwater concrete placement

Underwater weapons

Underwater weapons – Weapons that are intended for use underwater

Limpet mine – A type of naval mine which is attached to a target by magnets
Speargun – Underwater fishing implement
- Hawaiian sling – Simple form of underwater speargun
- Polespear – Basic rubber launched underwater fishing spear
Underwater firearm – Firearms that can be effectively fired underwater
- Gyrojet – Firearm that fires small rocket projectiles
- Mk 1 Underwater Defense Gun – Underwater firearm developed by the United States during the Cold War
- Powerhead (firearm) – Specialized firearm used underwater that is fired when in direct contact with the target
- Underwater pistols
  - Heckler & Koch P11 – Five-barreled underwater rocket dart pistol
  - SPP-1 underwater pistol – Soviet four-barreled underwater dart pistol
- Underwater revolvers
  - AAI underwater revolver – Six-round amphibious revolver for naval use
- Underwater rifles
  - ADS amphibious rifle – Russian bullpup assault rifle for combat divers
  - APS underwater rifle – Soviet underwater assault firearm firing unrifled steel flechettes
  - ASM-DT amphibious rifle – Russian folding stock underwater firearm

Diving support personnel

There are also diver support activities which require assessed competence and registration for which formal training may be required.

Diving team – Group of people working together to enhance dive safety and achieve a task
- Bellman (diving) – The member of a dive team who acts as stand-by diver and tender from the diving bell
- Compressor operator – Person competent to operate a diving air compressor
- Diver's attendant, also known as dive tender – Assistant for a diver
- Diving medical examiner – A medical practitioner registered to assess medical fitness to dive
- Diving medical practitioner – Specialist in diagnosis, treatment and prevention of disorders caused by underwater diving
- Diving Medical Technician, also known as Diver medic – Person trained in advanced first aid for divers
- Diving safety officer – Administrator of a US university's research diving safety program
- Diving supervisor – Professional diving team leader responsible for safety
- Diving systems technician – A competent person who maintains and repairs diving life-support equipment
- Gas man (diving), also known as gas panel operator, rack operator, or diving gas supply manifold operator – Member of a surface-supplied diving team who operates the breathing gas panel
- Life support technician – A member of a saturation diving team who operates the surface habitat
- Stand-by diver – A member of a dive team who is ready to assist or rescue the working diver
Scuba gas blender – Person competent to blend breathing gases for scuba diving
- Nitrox blender – Person competent to blend nitrox for scuba diving
- Trimix blender – Person competent to blend trimix breathing gases for scuba diving
Dive boat skipper – Person in command of a dive boat
Divemaster, also known as dive leader, dive guide – Recreational dive leader certification and role

Science of underwater diving

The diving environment

Plunging breaker

Lago Licancabur, site of world's highest ever altitude dive.

Entrance to Peacock Springs Cave System

Underwater diving environment – The underwater environment to which a diver may be exposed

List of diving environments by type – Variety of environments that people may dive in
Underwater environment – Aquatic or submarine environment
Open-water diving – Diving with access to breathable air of the atmospher
Altitude diving – Underwater diving at altitudes above 300 m
Cave diving – Diving in water-filled caves
Deep diving – Underwater diving to a depth beyond the norm accepted by the associated community
Ice diving – Underwater diving under ice
Muck diving – Recreational diving on a loose sedimentary bottom
Night diving – Underwater diving during the hours of darkness
Recreational dive sites – Places that divers go to enjoy the underwater environment
Wreck diving – Recreational diving on wrecks
Physical and biological aspects of the diving environment
- Algal bloom – Spread of planktonic algae in water
- Breaking wave, also known as Surf – Wave that becomes unstable as a consequence of excessive steepness
- Ocean current – Directional mass flow of oceanic water
- Current (stream) – Flow of water in a natural watercourse due to gravity
- Ekman transport – Net transport of surface water perpendicular to wind direction
- Halocline – Stratification of a body of water due to salinity differences
- Hazards of the aquatic environment represented by List of diving hazards and precautions#The aquatic environment –
- Hazards of the specific diving environment represented by List of diving hazards and precautions#The specific diving environment –
- List of diving hazards and precautions – Hazards associated with underwater diving
- Longshore current – Inshore current running parallel to the shoreline
- Overfall current – A turbulent area of water caused by a strong current over an underwater ridge, or by currents meeting.
- Rip current – Water current moving away from shore
- Stratification – Layering of a body of water due to density variations
- Surge (wave action) currently represented by Waves and shallow water – the component of wave motion in the direction of wave front propagation particularly close to and parallel with the bottom
- Thermocline – Distinct layer of temperature change in a body of water
- Tidal race – Fast-moving tidal flow passing through a constriction, forming waves, eddies and strong currents
- Tide – Rise and fall of the sea level under astronomical gravitational influences
- Turbidity – Cloudiness of a fluid
- Undertow (water waves) – Return flow below (nearshore) water waves.
- Upwelling – Oceanographic phenomenon of wind-driven motion of ocean water

Physics of underwater diving

Views through a flat mask, above and below water

Physics of underwater diving – Aspects of physics which affect the underwater diver

Buoyancy – Upward force that opposes the weight of an object immersed in fluid
- Archimedes' principle – Buoyancy principle in fluid dynamics
- Neutral buoyancy – Equilibrium between buoyancy and weight of an immersed object
Diffusion – Transport of dissolved species from the highest to the lowest concentration region
- Molecular diffusion – Thermal motion of liquid or gas particles at temperatures above absolute zero
- Permeation – Penetration of a liquid, gas, or vapor through a solid
Force – Influence that can change motion of an object
- Weight – Force on a mass due to gravity
Ideal gas law – Equation of the state of a hypothetical ideal gas
- Combined gas law – Combination of Charles', Boyle's and Gay-Lussac's gas laws
- Amontons' law – Relationship between pressure and temperature of a gas at constant volume
- Boyle's law – Relation between gas pressure and volume
- Charles's law – Relationship between volume and temperature of a gas at constant pressure
- Gay-Lussac's law – Relationship between pressure and temperature of a gas at constant volume
Pressure – Force distributed over an area
- Ambient pressure – Pressure of the surrounding medium
- Atmospheric pressure – Static pressure exerted by the weight of the atmosphere
- Hydrostatic pressure – The static pressure exerted by the weight of the fluid column above the point
  - Metre sea water – Unit of pressure equal to one tenth of a bar
- Partial pressure – Pressure of a component gas in a mixture
  - Dalton's law – Empirical law of partial pressures
  - Oxygen fraction – Volumetric proportion of oxygen to other constituents in a breathing gas
- Torricellian chamber – Type of cave chamber
Psychrometric constant – Relation of the partial pressure of water in air to temperature
Solubility – Capacity of a substance to dissolve in a homogeneous way
- Henry's law – Gas law regarding proportionality of dissolved gas
- Solution – Homogeneous mixture of a solute and a solvent
- Supersaturation – State of a solution that contains more solute than can be dissolved at equilibrium
Surface tension – Tendency of a liquid surface to shrink to reduce surface area
- Hydrophobe – Molecule or surface that has no attraction to water
- Surfactant – Substance that lowers the surface tension between a liquid and another material
Underwater vision – The ability to see objects underwater
- Snell's law, also known as Law of refraction – Formula for refraction angles
Work of breathing (WoB) – Energy expended to inhale and exhale a breathing gas

Physiology of underwater diving

Diagram of the human circulatory system

Decompression profiles based on the Thermodynamic model compared with the US Navy table for the same depth and bottom time

Diagram of the human respiratory system

Human physiology of underwater diving – Influences of the underwater environment on the physiology of human divers

Circulatory system – Organ system for circulating blood in animals
- Patent foramen ovale – A heart defect present at birth
- Blood–air barrier – Membrane separating alveolar air from blood in lung capillaries
- Blood shift – Blood flow to the extremities redistributed to the head and torso during a breathhold dive
- Perfusion – Passage of fluid through the circulatory or lymphatic system to an organ or tissue
- Pulmonary circulation – Part of the circulatory system which carries blood from heart to lungs and back to the heart
- Systemic circulation – Portion of the cardiovascular system which transports oxygenated blood away from the heart
Cold shock response – Physiological response to sudden exposure to cold
Dead space (physiology) – Inhaled air not part of gas exchange
Diving reflex – The physiological responses to immersion of air-breathing vertebrates
Metabolism – Set of chemical reactions in organisms
Physiology of decompression – The physiological basis for decompression theory and practice
- Decompression theory – Theoretical modelling of decompression physiology
  - Bühlmann decompression algorithm, also known as Buhlmann algorithm – Mathematical model of tissue inert gas uptake and release with pressure change
  - Equivalent air depth – Method of comparing decompression requirements for air and a given nitrox mix
  - Gradient factor in decompression modelling – A way for users to adjust the conservatism of a decompression algorithm in software
  - Haldane's decompression model – Decompression model developed by John Scott Haldane
  - Lipid – Substance of biological origin that is soluble in nonpolar solvents
  - Oxygen window – Physiological effect of oxygen metabolism on the total dissolved gas concentration in venous blood
  - Reduced gradient bubble model – Decompression algorithm
  - Thalmann algorithm – Mathematical model for diver decompression
  - Thermodynamic model of decompression – Early model in which decompression is controlled by volume of gas bubbles forming in tissues
  - Uncontrolled decompression – Unplanned drop in the pressure of a sealed system
  - Varying Permeability Model – Decompression model and algorithm based on bubble physics
Respiration (physiology) – Exchange of gases between environment and tissues
- Artificial gills (human) – Hypothetical devices to extract oxygen from water
- Breathing – Process of moving air in and out of the lungs
  - Work of breathing – Energy expended to inhale and exhale a breathing gas
- Carbon dioxide retention – A tendency to retain abnormally high tissue carbon dioxide levels
- Gas exchange – Process by which gases diffuse through a biological membrane
- Hypocapnia – State of reduced carbon dioxide in the blood
- Normocapnia – Normal arterial carbon dioxide levels
- Respiratory exchange ratio – Ratio between the metabolic production of carbon dioxide and the uptake of oxygen
- Respiratory quotient – Ratio of carbon dioxide produced by the body to oxygen consumed by the body
- Respiratory system – Biological system in animals and plants for gas exchange
- Tissue (biology) – Group of similar cells performing a specific function
Underwater vision – The ability to see objects underwater

Diving medicine, disorders and treatment

Oxygen therapy in a multiplace hyperbaric chamber is often delivered via built in breathing systems.

Monoplace chambers can be used for hyperbaric oxygen therapy if the patient is stable

Diving medicine

Diving medicine – Diagnosis, treatment and prevention of disorders caused by underwater diving

Fitness to dive, also known as Medical fitness to dive – Medical fitness to function underwater
Diving medical examiner – A medical practitioner registered to assess medical fitness to dive
Diving medical practitioner – Specialist in diagnosis, treatment and prevention of disorders caused by underwater diving
Diving medical technician – Person trained in advanced first aid for divers
Hyperbaric medicine – Medical treatment at raised ambient pressure

Diving disorders and treatment

Mask squeeze - a mild form of barotrauma

Staged image showing how victims may black out quietly underwater, often going unnoticed.

Diving disorders – Physiological disorders resulting from underwater diving

List of signs and symptoms of diving disorders – Evidence of physiological disorders resulting from underwater diving
Drowning – Respiratory impairment caused by submersion in liquid
- Laryngospasm – Involuntary contraction of the vocal folds restricting inhalation
Dysbarism – Medical conditions resulting from changes in ambient pressure
- Barotrauma – Injury caused by external fluid pressure
  - Arterial gas embolism – Vascular blockage by gas bubbles
  - Pulmonary barotrauma – Lung over-pressure and squeeze injuries
- Compression arthralgia – Joint pain caused by fast compression to high ambient pressure
- Decompression illness – Disorders arising from ambient pressure reduction
  - Decompression sickness – Disorder caused by dissolved gases forming bubbles in tissues
    - Dysbaric osteonecrosis – Ischemic bone disease caused by decompression bubbles
      - Avascular necrosis – Death of bone tissue due to interruption of the blood supply
    - Inner ear decompression sickness – Medical condition caused by inert gas bubbles forming out of solution
    - Isobaric counterdiffusion – Gaseous diffusion through body tissue at constant total pressure
    - Taravana – Decompression sickness after breath-hold diving
    - Therapeutic recompression – Recompression to reduce symptoms of decompression illness
      - Hyperbaric treatment schedules – Planned hyperbaric exposure using a specified breathing gas as medical treatment
      - In-water recompression – In-water treatment for decompression sickness
Hypercapnia – Abnormally high tissue carbon dioxide levels
Hypothermia – Human body core temperature below 35 °C (95 °F)
Hypoxia (medicine) – Medical condition of lack of oxygen in the tissues
- Freediving blackout – Loss of consciousness caused by cerebral hypoxia towards the end of a breath-hold dive
- Latent hypoxia – Lung gas and blood oxygen concentration sufficient to support consciousness only at depth
Motion sickness, also known as seasickness – Nausea caused by motion or perceived motion
Oxygen therapy – Use of oxygen as a medical treatment
- Built-in breathing system (BIBS) – System for supply of breathing gas on demand within a confined space
Surfer's ear – Common name for an abnormal bone growth within the external ear canal
Toxicity – Dose dependant harmfulness of substances
- Carbon monoxide poisoning – Toxic effects of carbon monoxide
- Nitrogen narcosis – Reversible narcotic effects of respiratory nitrogen at elevated partial pressures
  - Equivalent narcotic depth – Method for comparing the narcotic effects of a mixed diving gas with air
- Oxygen toxicity – Toxic effects of breathing oxygen at high partial pressures
  - Maximum operating depth – Depth below which the partial pressure of oxygen (pO2) of the gas mix exceeds an acceptable limit
- High-pressure nervous syndrome – Disorder from breathing helium based gas
- Hydrogen narcosis – Psychotropic state induced by breathing hydrogen at high partial pressures
- Hydrogen sulfide – Poisonous, corrosive and flammable gas
Vertigo – Type of dizziness where a person has the sensation of moving or surrounding objects moving
- Alternobaric vertigo – Dizziness resulting from unequal pressures in the middle ears

Diving safety

A dive team listens to a safety brief from their dive supervisor

Early testing for oxygen toxicity in divers

Tags in place in a powerplant after it was shut down

Folding lockout hasp, allowing six padlocks to lock out one device.

Checklists reduce the risk of omitting a step in a procedure

Diving safety – Risk management of underwater diving activities

Checklist – Aide-memoire to ensure consistency and completeness in carrying out a task
Code of practice (CoP) – Set of written rules which specifies how people working in a particular occupation should behave
Dive team – A group of people working together to enhance dive safety and achieve a task
- Professional diving – Underwater diving where divers are paid for their work
- Diving supervisor – Professional diving team leader responsible for safety
- Stand-by diver – A member of a dive team who is ready to assist or rescue the working diver
- Bellman (diving) – The member of a dive team who acts as stand-by diver and tender from the diving bell
- Diver's attendant – Assistant for a diver
- Life support technician – A member of a saturation diving team who operates the surface habitat
- Chamber operator – A person who operates a diving chamber
- Diving systems technician – A competent person who maintains and repairs diving life-support equipment
Divemaster – Recreational dive leader certification and role
Diving hazards – Agents and situations that pose a threat to the underwater diver
- Silt out – Reduction of underwater visibility by disturbing silt deposits
- Task loading – Relationship between operator capacity and the accumulated activities that must be done
Diver rescue – Rescue of a distressed or incapacitated diver
- Rescue Diver – Recreational scuba certification emphasising emergency response and diver rescue
Doing It Right (scuba diving) (DIR) – Technical diving safety philosophy
Hazardous Materials Identification System – Numerical hazard rating using colour coded labels
Human factors in diving equipment design – Influence of the interaction between the user and the equipment on design
Human factors in diving safety – The influence of physical, cognitive and behavioral characteristics of divers on safety
Occupational safety and health, also known as Occupational health and safety – Field concerned with the safety, health and welfare of people at work
- Safety culture – Risk-averse attitudes
Operations manual – Authoritative document of how things should be done in an organisation
- Emergency response plan – Action to be taken in specific emergencies
- Evacuation plan – Plan for removal of personnel from a high risk area or a developing incident to a safer place
- Standard operating procedure (SOP) – Set of detailed instructions to assist in workplace safety
Risk management – Identification, evaluation and control of risks
- Hazard analysis (HAZID) – Method for assessing risk
- Hazard identification – First step of risk assessment and management
- Job safety analysis (JSA) – Procedure to integrate safety practices into a particular task
- Risk assessment – Estimation of risk associated with exposure to a given set of hazards
- Risk control – Process in which identified risks are reduced or mitigated
  - Hierarchy of hazard controls – System used in industry to eliminate or minimize exposure to hazards
- Incident pit – Conceptual model for explaining incident development and recovery
- Lockout–tagout (LOTO) – Safe isolation of dangerous equipment during maintenance or testing
- Permit-to-work – Work safety management system
- Redundancy – Duplication of critical components to increase reliability of a system
- Safety data sheet, also known as Material safety data sheet – Sheet listing work-related hazards of a product or substance
Scuba diving fatalities – Deaths occurring while scuba diving or as a consequence of scuba diving
Single point of failure – A part whose failure will disrupt the entire system
Water safety – Human safety in the vicinity of bodies of water

Diving incidents, rescues, and fatalities

The decompression chamber at the moment the Byford Dolphin accident occurred. D1–D4 are divers; T1 and T2 are dive tenders.

Incidents and people involved in a notable incident while diving or during a diving operation.

Early diving incidents
- John Day (carpenter) – First recorded death in a diving chamber
- Charles Spalding – Scottish confectioner and amateur diving bell designer
- Ebenezer Watson – nephew of Charles Spalding and died in the same accident
Freediving incidents
- Loïc Leferme – French freediving record breaker
- Audrey Mestre – French world record-setting freediver
- Nicholas Mevoli – American freediver who died while attempting to set a record (1981–2013)
- Natalia Molchanova – Russian multiple world record holding freediver (1962–2015)
Professional diving incidents
- Johnson Sea Link accident – Manned submersible incident in which two divers died
- Offshore diving incidents
  - Byford Dolphin#Diving bell accident – Semi-submersible offshore drilling rig
  - Drill Master diving accident – Fatal diving bell accident off Norway in 1974
  - Star Canopus diving accident – Fatal offshore diving bell accident in 1978
  - Venture One diving accident – Saturation diving fatality in the North Sea in 1977
  - Waage Drill II diving accident – Fatal saturation diving accident in the North Sea in 1975
  - Wildrake diving accident – Fatal offshore diving accident in Scotland, 1979
- Rescues involving diving
  - Tham Luang cave rescue – 2018 international rescue in Thailand
  - Harrison Odjegba Okene – Nigerian ship's cook, rescued after 60 hours in a sunken tugboat
- Professional diving fatalities
  - Roger Baldwin (diver) represented by Waage Drill II diving accident – Fatal saturation diving accident in the North Sea in 1975
  - John Bennett (diver) – British technical diver and former record holder lost in commercial diving incident
  - Victor F. Guiel Jr. represented by Wildrake diving accident – Fatal offshore diving accident in Scotland, 1979
  - Craig M. Hoffman represented by Venture One diving accident – Saturation diving fatality in the North Sea in 1977
  - Peter Henry Michael Holmes represented by Waage Drill II diving accident – Fatal saturation diving accident in the North Sea in 1975
  - Edwin Clayton Link represented by Johnson Sea Link accident – Manned submersible incident in which two divers died
  - Gerard Anthony Prangley represented by Star Canopus diving accident – Fatal offshore diving bell accident in 1978
  - Per Skipnes represented by Drill Master diving accident – Fatal diving bell accident off Norway in 1974
  - Robert John Smyth represented by Drill Master diving accident – Fatal diving bell accident off Norway in 1974
  - Albert D. Stover represented by Johnson Sea Link accident – Manned submersible incident in which two divers died
  - Richard A. Walker represented by Wildrake diving accident – Fatal offshore diving accident in Scotland, 1979
  - Lothar Michael Ward represented by Star Canopus diving accident – Fatal offshore diving bell accident in 1978
  - Joachim Wendler – German aquanaut (1939–1975)
  - Death of Bradley Westell – Fatal diving accident in the North Sea in 1995
  - Arne Zetterström – Swedish diver and researcher (1917–1945)
Scuba diving fatalities – Deaths occurring while scuba diving or as a consequence of scuba diving
- Ricardo Armbruster – Spanish ecologist, adventurer and entrepreneur
- Allan Bridge – American conceptual artist (1945–1995)
- David Bright (diver) – Wreck diver
- Berry L. Cannon – American aquanaut who died in a diving incident (1935–1969)
- Cotton Coulson – Photographer known for his work for National Geographic magazine
- E. Yale Dawson – American botanist and taxonomist
- Deon Dreyer – South African diver
- Milan Dufek – Czech singer, composer and musician
- Sheck Exley – American cave and deep diving pioneer and record breaker
- Maurice Fargues – French navy diver and first scuba fatality using aqualung for a depth record attempt
- Guy Garman – Scuba diver who died in a world record attempt
- Steve Irwin – Australian zookeeper, conservationist and television personality (1962–2006)
- Henry Way Kendall – American particle physicist who won the Nobel Prize in Physics
- Artur Kozłowski (speleologist) – Polish cave diver (1977–2011)
- Chris and Chrissy Rouse, represented by The Last Dive – Non-fiction book by Bernie Chowdhury about a double wreck diving fatality
- Kirsty MacColl – British singer and songwriter (1959–2000)
- Agnes Milowka – Australian cave diver
- François de Roubaix – French film score composer
- Dave Shaw – Australian technical diver and former record holder killed in a diving incident
- Wesley C. Skiles – American cave diver and cinematographer
- Dewey Smith – American aquanaut. Died in diving accident.
- Rob Stewart (filmmaker) – Canadian photographer, filmmaker and conservationist
- Esbjörn Svensson – Swedish jazz pianist
- Josef Velek – Czech journalist, author, and environmentalist (1939–1990)

Legal aspects of diving

Legal aspects of diving – How underwater diving and divers are affected by law

Civil liability in recreational diving – Legal duty of care, negligence and liability in recreational diving
Diving regulations – Stipulations of the delegated legislation regarding the practice of underwater diving – Legislation regulating diving activity, usually a branch of occupational health and safety.
Duty of care – Type of legal obligation
Investigation of diving accidents – Forensic investigation of underwater diving accidents
List of legislation regulating underwater diving – List of national and state legislation regulating underwater diving

Geography of diving

Recreational diver over a coral reef in the Red Sea

Recreational dive sites are specific places that recreational scuba divers go to enjoy the underwater environment or for training purposes. They include technical diving sites beyond the range generally accepted for recreational diving. In this context all diving done for recreational purposes is included. Professional diving tends to be done where the job is, and with the exception of diver training and leading groups of recreational divers, does not generally occur at specific sites chosen for their easy access, pleasant conditions or interesting features.

Recreational dive sites may be found in a wide range of bodies of water, and may be popular for various reasons, including accessibility, biodiversity, spectacular topography, historical or cultural interest and artifacts (such as shipwrecks), and water clarity. Tropical waters of high biodiversity and colourful sea life are popular recreational diving tourism destinations. South-east Asia, the Caribbean islands, the Red Sea and the Great Barrier Reef of Australia are regions where the clear, warm, waters, reasonably predictable conditions and colourful and diverse sea life have made recreational diving an economically important tourist industry.

Recreational divers may accept a relatively high level of risk to dive at a site perceived to be of special interest. Wreck diving and cave diving have their adherents, and enthusiasts will endure considerable hardship, risk and expense to visit caves and wrecks where few have been before. Some sites are popular almost exclusively for their convenience for training and practice of skills, such as flooded quarries. They are generally found where more interesting and pleasant diving is not locally available, or may only be accessible when weather or water conditions permit.

While divers may choose to get into the water at any arbitrary place that seems like a good idea at the time, a popular recreational dive site will usually be named, and a geographical position identified and recorded, describing the site with enough accuracy to recognise it, and hopefully, find it again. (Full article...)

History of underwater diving

Siebe's improved design in 1873.

History of underwater diving – Developments over time in the human activity

History of decompression research and development – Chronological list of notable events in the history of diving decompression.
History of scuba diving
- Vintage scuba – Early model scuba equipment and the ongoing activity of diving with it
List of researchers in underwater diving – People who made discoveries or inventions in the science or technology of underwater diving
Lyons Maritime Museum – Diving history museum in St. Augustine, Florida
Timeline of diving technology – Chronological list of notable events in the history of underwater diving equipment

Military and covert operations

Italian Maiale manned torpedo "Siluro San Bartolomeo" displayed at the Royal Navy Submarine Museum, Gosport, UK.

1982 invasion of the Falkland Islands – Argentine invasion of the Falklands
Exercise Paddington Diamond – Joint Bolivian-British-Swiss scuba diving expedition to Lake Titicaca
Raid on Algiers – Italian frogman raid on Allied ships in Algiers harbour in 1942
Defense against swimmer incursions – Methods of protection from incursions by divers and swimmers
Italian auxiliary ship Olterra – Undercover Italian auxiliary ship from World War II
Operation Algeciras – Argentine plan to sabotage a British warship in Gibraltar
Operation Thunderhead – American amphibious mission during the Vietnam War
Raid on Alexandria (1941) – Italian frogman raid on British warships
Sinking of the Rainbow Warrior – 1985 covert attack by French foreign intelligence service on a Greenpeace ship
USS Westchester County (LST-1167) – US Navy tank landing ship built in 1952

Underwater salvage operations

Salvage of Royal George

Salvage operations on HMS Royal George – Early salvage operations using bells and surface supplied divers
Salvage of the SS Egypt's gold – Recovery of bullion from wreck using an atmospheric pressure observation bell
Kursk submarine disaster#Salvage operation – Raising the wreck of a Russian nuclear submarine
USS Squalus represented by USS Sailfish (SS-192)#Sinking of Squalus and recommissioning as Sailfish – The successful rescue of the crew and later raising of the sunken vessel.

Training, certification, registration and standards

Commercial diver training at Blue Rock Quarry

Diver training

Diver training – Processes to develop the skills and knowledge to dive safely underwater
Diver certification – Certification as competent to dive to a specified standard

Diver training can be distinguished between recreational and occupational diver training. Recreational diver training tends to be split into small skill sets for customer convenience and provider profitability. Recreational diver training systems include training and registration of instructors and dive leaders for recreational diving

Recreational diver training – Training process for people who do not dive at work
- Adaptive Support Diver – Scuba diver trained to support divers with disabilities
- Advanced nitrox diver – Technical diving qualification to use multiple mixtures of oxygen enriched air
- Advanced Open Water Diver – Recreational scuba diving certification slightly above minimum entry level
- Advanced trimix diver – Recreational technical diving certification to use hypoxic trimix
- Altitude diver – Diver competent to plan decompression at altitude
- Autonomous diver – International minimum standard for entry level recreational scuba diver certification
- BSAC First Class Diver – Recreational diver competent to lead a group of divers carrying out a project
- Cave diver – Certification as competent to dive in flooded caves
- Cavern diver – Certification for diving under a natural overhead within the zone of natural light
- CMAS* scuba diver, also known as One Star Diver – Entry level recreational diving certification from CMAS
- CMAS** scuba diver, also known as Two Star Diver – Autonomous recreational scuba diving certification
- CMAS*** scuba diver, also known as Three Star Diver – Fully trained and experienced recreational diver
- CMAS**** scuba diver, also known as Four Star Diver – A three-star diver with a high level of competence and broad experience
- Dive leader, also known as Divemaster – Recreational diving certification and role
- Recreational diving instructor – Person who trains and assesses recreational divers
- Dry suit diver – Certification for diving in a dry suit
- Hypoxic trimix diver – Recreational technical diving certification level
- Low impact diver – Diver with the skills to avoid contact with the benthos
- Open Water Diver – Entry-level autonomous diver certification for recreational scuba diving
- Master Instructor – Grade of recreational dive instructor with some experience
- Master Scuba Diver – The highest non-leadership recreational scuba diver certification issued by some agencies
- Night diver – Certification of competence to scuba dive at night
- Nitrox diver – Recreational diving qualification to dive using oxygen enriched air
- Normoxic trimix diver – Recreational technical diving certification level
- PADI Delayed Surface Marker Buoy Diver – Diver trained to deploy a decompression buoy from depth
- PADI Peak Performance Buoyancy – PADI diver with buoyancy control skill
- Rebreather diver – Scuba diving qualification to use a rebreather
  - Seni-closed rebreather diver
  - Closed circuit rebreather diver
- Recreational trimix diver – Certification to dive with normoxic trimix with equivalent narcotic depth 80 ft or less
- Rescue Diver – Recreational scuba certification emphasising emergency response and diver rescue
- Search and recovery diver – Diver certified as trained in underwater search and recovery
- Scuba refresher course – Coaching to restore skills and knowledge
- Sidemount diver – Scuba certification for using scuba sets clipped to the sides of the harness
- Solo diver – Recreational diver diving without a dive buddy
- Supervised diver – Minimum requirements for a recreational diver to dive in open water under direct supervision
- Introductory diving – Non-certification scuba diving experience
- Underwater navigator – Diver competent to navigate in open water by compass or pilotage
- Underwater photographer, also known as Underwater digital photographer – Person who takes photographs underwater
- Underwater videographer – Diver trained in the use of video recorders underwater
- Wreck diver – Recreational diving certification as competent to dive on wrecks
Universal Referral Program – System to complete recreational scuba training with another instructor
World Recreational Scuba Training Council – Scuba diving standards body

Professional diver training is usually for registration based on mode of diving and requires a wider range of competence for a range of equipment skills and environments. Titles of certificates vary, but the basic competences are similar and may be internationally recognised by agreement.

Occupational diver training – Training of people employed as underwater divers
International Diving Regulators and Certifiers Forum (IDRCF) – International forum of professional diver accreditation organisations
- Professional scuba diver, also known as Commercial scuba diver – Person with skills and knowledge required for occupational scuba diving
- Surface-supplied air diver, also known as Inshore air diver – Person competent to dive with surface-supplied breathing apparatus
- Extended range surface-supplied air diver, also known as Offshore air diver – Surface-supplied offshore air diving to 50 msw using a wet bell and hot water suit
- Surface-supplied mixed gas diver, also known as Closed bell diver – Person competent to dive with mixed gas from a closed bell
- Saturation diver – Diver registered as competent for saturation diving

Scientific diving is occupational diving in the pursuit of scientific knowledge, and there may be different conditions that apply regionally regarding regulation and registration.

European Scientific Diving Panel – A panel of the European Network of Marine Research Institutes and Stations
- Advanced European Scientific Diver – A diver competent to organise a scientific diving team
- European Scientific Diver – A diver competent to perform as a member of a scientific diving team.

Diver certification organisations

List of diver certification organizations – Agencies which issue certification for competence in diving skills

Occupational diver certification authorities
- Australian Diver Accreditation Scheme (ADAS) – Australian based international occupational diver accreditation organisation
- Divers Institute of Technology – Private, commercial educational institution for the training of commercial divers
- Emergency Response Diving International (ERDI) – American organisation for training and certification of emergency response divers
- Health and Safety Executive (HSE) – United Kingdom government agency
- South African Department of Employment and Labour – Department of the South African government responsible for matters related to employment
Recreational diver certification agencies
- Freediver certification agencies
  - AIDA International (AIDA) – Worldwide rule- and record-keeping body for competitive breath-hold events
  - Confédération Mondiale des Activités Subaquatiques (CMAS) – International organisation for underwater activities
  - Performance Freediving International (PI) – Freediver training agency
  - Scuba Schools International (SSI) – Recreational scuba and freediving training and certification agency
- Recreational scuba certification agencies
  - American Nitrox Divers International (ANDI) – Recreational diver training and certification agency
  - CEDIP members
    - Association nationale des moniteurs de plongée (ANMP) – French recreational diver training and certification agency
  - British Sub-Aqua Club (BSAC) – Recreational diving club, training and certification agency based in the UK
    - Comhairle Fo-Thuinn (CFT) – Governing body for recreational diving and underwater hockey in Ireland
  - Confédération Mondiale des Activités Subaquatiques (CMAS) – International organisation for underwater activities
    - CMAS Europe – Non-profit branch of the world underwater federation representing European affiliates – the branch of the world underwater federation representing European affiliates
    - Fédération Française d'Études et de Sports Sous-Marins (FFESSM) – French diver training and certification agency
    - Federazione Italiana Attività Subacquee (FIAS) – Italian non-profit recreational diver training organisation affiliated to CMAS
    - Federación Española de Actividades Subacuáticas (FEDAS) – Spanish national federation for underwater activities, affiliated to CMAS
    - Israeli Diving Federation (TIDF) – Israeli recreational diver training and certification agency
    - Nederlandse Onderwatersport Bond (NOB) – Dutch governing body for underwater sports
    - Sub-Aqua Association (SAA) – British recreational diver training and certification organisation
    - Scuba Educators International (SEI) – Recreational diver training and certification agency
    - Türkiye Sualtı Sporları Federasyonu (TSSF) – Turkish national governing body for underwater sport and lifesaving
  - European Underwater Federation certification
    - Israeli Diving Federation (TIDF) – Israeli recreational diver training and certification agency
    - National Academy of Scuba Educators (NASE) – Recreational scuba training and certification agency
    - Scuba Schools International (SSI) – Recreational scuba and freediving training and certification agency
  - Global Underwater Explorers (GUE) – Recreational/technical scuba training and certification agency
  - International Association for Handicapped Divers (IAHD) – Non-profit organisation based in the Netherlands
  - International Association of Nitrox and Technical Divers (IANTD) – Recreational and technical scuba training and certification agency
  - National Association for Cave Diving (NACD) – American non-profit organization for improving cave diving safety
  - Scottish Sub Aqua Club (ScotSAC) – Scottish recreational diver training and certification agency
  - United Diving Instructors (UDI) – Recreational diver training and certification agency
  - Unified Team Diving (UTD) – a recreational diver training and certification agency
  - WRSTC and RSTC members
    - American Canadian Underwater Certifications (ACUC) – Recreational diver training and certification agency
    - International Diving Educators Association (IDEA)
    - National Association of Underwater Instructors (NAUI) – Non-profit training and certification agency association of scuba instructors
    - Professional Association of Diving Instructors (PADI) – Recreational diver training and certification agency
    - Professional Diving Instructors Corporation (PDIC) – Recreational diver training and certification agency
    - Professional Technical and Recreational Diving – Diver certification agency
    - Rebreather Association of International Divers (RAID) – Recreational diver training and certification agency
    - Scuba Diving International (SDI) – Recreational diver training and certification agency
    - Scuba Schools International (SSI) – Recreational scuba and freediving training and certification agency
  - YMCA SCUBA Program – Defunct recreational diver training and certification agency
- Technical diver certification agencies
  - Cave diving certification agencies
    - Cave Divers Association of Australia (CDAA) – Association to represent cave divers and administrate and support cave diving in Australia
    - Cave Diving Group (CDG) – UK based cave diver training and certification agency
    - National Association for Cave Diving (NACD) – American non-profit organization for improving cave diving safety
  - American Nitrox Divers International (ANDI) – Recreational diver training and certification agency
  - British Sub-Aqua Club (BSAC) – Recreational diving club, training and certification agency based in the UK
  - Diving Science and Technology (DSAT) – PADI affiliate and developer of recreational decompression planning tools
  - Federazione Italiana Attività Subacquee (FIAS) – Italian non-profit recreational diver training organisation affiliated to CMAS
  - Global Underwater Explorers (GUE) – Recreational/technical scuba training and certification agency
  - International Association of Nitrox and Technical Divers (IANTD) – Recreational and technical scuba training and certification agency
  - National Association of Underwater Instructors (NAUI) – Non-profit training and certification agency association of scuba instructors
  - Professional Association of Diving Instructors (PADI) – Recreational diver training and certification agency
  - Professional Diving Instructors Corporation (PDIC) – Recreational diver training and certification agency
  - Professional Technical and Recreational Diving – Diver certification agency
    - Rebreather Association of International Divers (RAID) – Recreational diver training and certification agency
  - Technical Diving International (TDI) – Technical diver training and certification agency
  - Trimix Scuba Association (TSA) – Recreational technical scuba training and certification agency
  - Technical Extended Range (TXR) – Recreational scuba and freediving training and certification agency
  - Unified Team Diving (UTD) – A recreational and technical diver training and certification agency
Scientific diver certification authorities
- American Academy of Underwater Sciences (AAUS) – American diving standards organisation
- CMAS Scientific Committee – International organisation for underwater activities
- South African Department of Employment and Labour – Department of the South African government responsible for matters related to employment

Organisations setting international standards and codes of practice for diving and diver training

Association of Diving Contractors International (ADCI) – Non-profit organization for promoting standards and knowledge for commercial diving
European Underwater Federation (EUF) – Umbrella organisation representing scuba diver training organisations in Europe
International Diving Regulators and Certifiers Forum (IDRCF) – International forum of professional diver accreditation organisations
International Diving Schools Association (IDSA) – Organisation to develop common standards for commercial diver training
International Marine Contractors Association (IMCA) – International trade association for the marine contracting industry
International Organization for Standardization (ISO) – International standards development organization
Rebreather Training Council (RTC) – Organisation to coordinate rebreather training standards
World Recreational Scuba Training Council (WRSTC) – Scuba diving standards body
Scientific diving standards organizations
- American Academy of Underwater Sciences (AAUS) – American diving standards organisation
- European Scientific Diving Panel – A panel of the European Network of Marine Research Institutes and Stations

Commercial diving schools

Divers Academy International – Technical educational institution in New Jersey that offers training in commercial diving

Underwater diving organisations

Diver membership organisations

Freediver federations
- AIDA International (AIDA) – Worldwide rule- and record-keeping body for competitive breath-hold events
- AIDA Hellas – National representative of AIDA International in Greece
- British Freediving Association (BFA) – British affiliate to AIDA International
- Confédération Mondiale des Activités Subaquatiques (CMAS) – International organisation for underwater activities
Recreational and technical scuba clubs and associations
- British Sub-Aqua Club (BSAC) – Recreational diving club, training and certification agency based in the UK
- Cave Divers Association of Australia (CDAA) – Association to represent cave divers and administrate and support cave diving in Australia
- Cave Diving Group (CDG) – UK based cave diver training and certification agency
- International Association for Handicapped Divers (IAHD) – Non-profit organisation based in the Netherlands
- National Association for Cave Diving (NACD) – American non-profit organization for improving cave diving safety
- Woodville Karst Plain Project (WKPP) – Project and organization to map the underwater cave systems of the Woodville Karst Plain
- Military services recreational diving organisations
  - Naval Air Command Sub Aqua Club – British organization within the Royal Navy
Scientific, archaeological and historical diving organisations
- Historical Diving Society
- Nautical Archaeology Society (NAS) – British organisation to further research in nautical archaeology for the public benefit
- Save Ontario Shipwrecks (SOS) – A provincial heritage NGO in Ontario, Canada
- Sea Research Society – American nonprofit for marine research
National underwater-sports federations
- Australian Underwater Federation (AUF) – Governing body for underwater sports in Australia
- British Octopush Association (BOA) – National body for underwater hockey in the United Kingdom
- British Underwater Sports Association (BUSA) – British affiliate to the world underwater federation sports committee.
- Comhairle Fo-Thuinn (CFT) – Governing body for recreational diving and underwater hockey in Ireland
- Federación Española de Actividades Subacuáticas (FEDAS) – Spanish national federation for underwater activities, affiliated to CMAS
- Fédération Française d'Études et de Sports Sous-Marins (FFESSM) – French diver training and certification agency
- South African Underwater Sports Federation (SAUSF) – Official World Underwater Federation representative body in the Republic of South Africa
- Türkiye Sualtı Sporları Federasyonu (TSSF) – Turkish national governing body for underwater sport and lifesaving
- Underwater Society of America (USOA) – American national representative organization for underwater sport.
International underwater-sports federations
- AIDA International (AIDA) – Worldwide rule- and record-keeping body for competitive breath-hold events
- Confédération Mondiale des Activités Subaquatiques (CMAS) – International organisation for underwater activities

Diver nature conservation organisations

Artificial Reef Society of British Columbia (ARSBC) – Canadian non-profit to create artificial reefs for habitat enhancement and recreation
Green Fins – Organisation in South East Asia for preservation of coral reefs by improving diver behavior
National Speleological Society – Cave Diving Section (NSS-CDS) – Organization for exploration, conservation, and study of caves in the United States

Diving industry trade associations

Diving Equipment and Marketing Association (DEMA) – International trade association for the recreational diving equipment industry

Underwater environmental research organisations

National Oceanic and Atmospheric Administration (NOAA) – US government scientific agency
Reef Life Survey (RLS) – Marine life monitoring programme based in Hobart, Tasmania
South African Environmental Observation Network (SAEON) – A network to perform long-term ecological research in South Africa and surrounding waters

Diving medical research organisations

Aerospace Medical Association – Professional organization in aviation, space, hyperbaric and environmental medicine
Divers Alert Network (DAN) – International group of not-for-profit organizations for improving diving safety
Diving Diseases Research Centre (DDRC) – British hyperbaric medical organisation
Diving Medical Advisory Council (DMAC) – Independent organisation of diving medical specialists from Northern Europe
European Diving Technology Committee (EDTC) – International organisation for improving professional diver safety
European Underwater and Baromedical Society (EUBS) – Source of information for diving and hyperbaric medicine
National Board of Diving and Hyperbaric Medical Technology – Non-profit organization for education and certification in diving and hyperbaric medicine
Naval Submarine Medical Research Laboratory – U.S. Navy research unit for submarine and diving medicine
Royal Australian Navy School of Underwater Medicine – Unit based in Sydney, Australia.
Rubicon Foundation – Non-profit organization for promoting research and information access for underwater diving
South Pacific Underwater Medicine Society (SPUMS) – Publisher for diving and hyperbaric medicine and physiology
Southern African Underwater and Hyperbaric Medical Association (SAUHMA) – Special interest group of the Council of the South African Medical Association
Undersea and Hyperbaric Medical Society (UHMS) – US based organisation for research and education in hyperbaric physiology and medicine.
United States Navy Experimental Diving Unit (NEDU) – The primary source of diving and hyperbaric operational guidance for the US Navy

Underwater diving publications

Books and manuals

The Darkness Beckons – History of UK cave diving by Martyn Farr
Goldfinder – Autobiography of British diver and treasure hunter Keith Jessop
The Last Dive – Non-fiction book by Bernie Chowdhury about a double wreck diving fatality
Shadow Divers – Book by Robert Kurson recounting the discovery of a World War II German U-boat wreck
The Silent World: A Story of Undersea Discovery and Adventure – Book by Jacques-Yves Cousteau and Frédéric Dumas
Basic Cave Diving: A Blueprint for Survival – Book on cave diving safety by Sheck Exley
Exploration and Mixed Gas Diving Encyclopedia – Tom Mount, Joseph Dituri, Eds
Deep diving: an advanced guide to physiology, procedures and systems
Diving manual A document providing extensive general information on the equipment, procedures and theoretical basis of underwater diving.
- NOAA Diving Manual – Training and operations manual for scientific diving Scientific diving manual published by the National Oceanographic and Atmospheric Administration
- Professional Diver's Handbook John Bevan Ed. A manual of offshore diving
- U.S. Navy Diving Manual – Training and operations handbook
Diving Medicine for Scuba Divers – Carl Edmonds, Bart McKenzie, Robert Thomas
Bennett and Elliott's physiology and medicine of diving Alf O. Brubakk, Tom S. Neuman, Eds
The Underwater Handbook: A Guide to Physiology and Performance for the Engineer – Charles Shilling, Ed.

Legislation

List of legislation regulating underwater diving – List of national and state legislation regulating underwater diving
Diving regulations – Stipulations of the delegated legislation regarding the practice of underwater diving
Diving at Work Regulations 1997 – UK legislation regulating all aspects of professional diving

Codes of practice

(National or international codes of practice for diving)

Code of practice – Set of written rules which specifies how people working in a particular occupation should behave
IMCA Code of Practice for Offshore Diving – Guidance document for member organisations A voluntary code of industry best practice followed by members of the International Marine Contractors Association.
Code of Practice for Scientific Diving: Principles for the Safe Practice of Scientific Diving in Different Environments – Document published by UNESCO

Standards

(National or international standards relating to diving equipment or practices)

Buoyancy compensators

EN 1809:1998 Diving accessories. Buoyancy compensators. Functional and safety requirements, test methods.
EN 1809:2014+A1:2016 Diving equipment. Buoyancy compensators. Functional and safety requirements, test methods.

Depth gauges

EN 13319:2000 Diving accessories. Depth gauges and combined depth and time measuring devices. Functional and safety requirements, test methods.

Diver training

ISO 24801 – International training standards for recreational scuba Recreational diving services – Requirements for the training of recreational scuba divers
ISO 21417 Recreational diving services – Requirements for training on environmental awareness for recreational divers

Diving masks

GOST 20568:1975 compliant Russian and Ukrainian diving masks

ANSI Z87.11:1985 Underwater Safety. Recreational Skin and Scuba Diving. Lenses for Masks.
BN-82/8444-17.01 Gumowy sprzęt pływacki - Maski pływackie (Rubber swimming equipment - Swimming masks).
BS 4532:1969 Specification for snorkels and face masks. Amended 1977.
CNS 12497:1989 潛水鏡. Diving mask.
CNS 12498:1989 潛水鏡檢驗法. Method of test for diving mask.
DIN 7877:1980 Tauch-Zubehör. Tauchbrillen. Sicherheitstechnische Anforderungen und Prüfung. Diving accessories for skin divers. Diver's masks. Requirements and testing.
EN 16805:2015 Diving equipment. Diving mask. Requirements and test methods.
GOST 20568:1975 Маски резиновые для плавания под водой. Общие технические условие. Rubber masks for submarine swimming. General specifications.
ÖNORM S 4225 Tauch-Zubehör; Tauchmasken (Tauchbrillen); Sicherheitstechnische Anforderungen, Prüfung, Normkennzeichnung. Diving accessories; divers’ masks; safety requirements, testing, marking of conformity.

Dry suits

EN 14225-2:2002 Diving suits. Dry suits. Requirements and test methods.
EN 14225-2:2017 Diving suits. Dry suits. Requirements and test methods.

Recreational diving services

ISO 21416 Recreational diving services – Requirements and guidance on environmentally sustainable practices in recreational diving

Snorkels

A range of 1970s snorkels made to British Standard BS 4532:1969

BS 4532:1969 Specification for snorkels and face masks. Amended 1977.
DIN 7878:1980 Tauch-Zubehör; Schnorchel; Maße, Anforderungen, Prüfung. Diving accessories for skin divers. Snorkel. Technical requirements of safety, testing.
DIN 7878:1991 Tauch-Zubehör; Schnorchel; Sicherheitstechnische Anforderungen und Prüfung. Diving accessories for skin divers. Snorkel. Safety requirements and testing.
EN 1972:1997 – European standard design and manufacture of snorkels Diving accessories. Snorkels. Safety requirements.
EN 1972:2015 Diving equipment. Snorkels. Requirements and test methods.
ÖNORM S 4223:1988 Tauch-Zubehör; Schnorchel; Abmessungen, sicherheitstechnische Anforderungen, Prüfung, Normkennzeichnung. Diving accessories; snorkels; dimensions, safety requirements, testing, marking of conformity.

Swimfins

Swim fin sole showing compliance with German standard DIN 7876:1980

BN-82/8444-17.02 Gumowy sprzęt pływacki - Płetwy pływackie (Rubber swimming equipment - Swimming fins).
DIN 7876:1980 Tauchzubehör. Schwimmflossen. Maße, Anforderungen und Prüfung. Diving accessories for skin divers. Flippers. Dimensions, requirements and testing.
EN 16804:2015 Diving equipment. Diving open heel fins. Requirements and test methods.
GOST 22469:1977 Ласты резиновые для плавания. Общие технические условия. Swimming rubber flippers. General specifications.
MIL-S-82258:1965 Military specification. Swim fins, rubber.
MS 974:1985 Specification for rubber swimming fins.
MS 974:2002 Specification for rubber swimming fins. First revision.
ÖNORM S 4224:1988 Tauch-Zubehör; Schwimmflossen; Abmessungen, sicherheitstechnische Anforderungen, Prüfung, Normkennzeichnung. Diving accessories; fins; dimensions, safety requirements, testing, marking of conformity.

Underwater breathing apparatus

BS EN 1802:2002 Transportable gas cylinders. Periodic inspection and testing of seamless aluminium alloy gas cylinders
BS EN 1968:2002 Transportable gas cylinders. Periodic inspection and testing of seamless steel gas cylinders
EN 14143-2003 Respiratory equipment - Self-contained re-breathing diving apparatus

Wetsuits

CNS 11251:1985 濕式潛水衣. Diving Wet Suit.
EN 14225-1:2005 Diving suits. Wet suits. Requirements and test methods.
EN 14225-1:2017 Diving suits. Wet suits. Requirements and test methods.

Journals and magazines

AquaCorps Magazine on technical diving, founded and edited by Michael Menduno
Alert Diver – Quarterly magazine published by DAN Quarterly magazine of DAN on diving safety and recreational diving matters
South Pacific Underwater Medical Society Journal – Journal covering underwater and hyperbaric medicine and physiology
Undersea and Hyperbaric Medicine – Journal covering underwater and hyperbaric medicine and physiology

Repositories

Rubicon Research Repository – Defunct database of environmental physiology documents

Recreational dive site guides

Notable dive site guides with Wikipedia article.

Index of recreational dive sites – Alphabetical listing of articles on porular places for recreational diving

Authors of publications about diving

Bob Halstead

Authors of general non-fiction works on diving topics who are the subjects of Wikipedia articles.

Michael C. Barnette – American underwater diver, author and founder of the Association of Underwater Explorers
Victor Berge – Swedish diving pioneer and author
Philippe Diolé – French author and undersea explorer
Gary Gentile – American author and pioneering technical diver
Bob Halstead – Underwater photographer, author, journalist and commentator on the recreational diving industry.
Jarrod Jablonski – Pioneer American cave diver, author and previous cave diving record holder
Trevor Jackson (diver) – Australian technical diver and author
Richie Kohler – American technical diver and shipwreck historian
Steve Lewis (diver) – Technical scuba diver and author
John Mattera – American wreck diver and author
Tom Mount – Pioneering technical and cave diver (1939–2022)

Documentaries

Documentary movies focused on underwater diving.

Ama Girls – 1958 film
Ben's Vortex – Documentary film on the disappearsnce of Ben McDaniel
Dave Not Coming Back – 2020 film by Jonah Malak
Diving into the Unknown – 2016 Finnish film directed by Juan Reina.
Dolphin Man – 2017 French film directed by Lefteris Charitos
Encounters at the End of the World – 2007 American documentary film by Werner Herzog
Last Breath (2019 film) – 2019 British documentary film about a diving accident
The Rescue (2021 film) – 2021 documentary film by Elizabeth Chai Vasarhelyi and Jimmy Chin
Sharkwater – 2006 Canadian documentary film on overexploitation of sharks
Sharkwater Extinction – 2018 Canadian documentary film directed by Rob Stewart
The Silent World – 1956 French documentary film co-directed by Jacques Cousteau and Louis Malle
The Trapped 13: How We Survived The Thai Cave – 2022 Thai documentary film
Voyage to the Edge of the World – 1976 French nature documentary
Wonders of the Sea 3D – 2019 film directed by Jean-Michel Cousteau and Jean-Jacques Mantello
World Without Sun – 1964 film by Jacques Cousteau

Underwater diving in popular culture

Movies, novels, TV series and shows, comics, graphic art, sculpture, games, myths, legends, and misconceptions. Fiction in general relating to all forms of diving, including hypothetical and imaginary methods, and other aspects of underwater diving which have become part of popular culture.

Researchers in diving medicine and physiology

John Scott Haldane c. 1910

Paul Bert

Arthur J. Bachrach – American psychologist and administrator (1923–2011)
Albert R. Behnke – US Navy physician and diving medicine researcher
Paul Bert – French zoologist, physiologist and politician (1833–1886)
George F. Bond – US Navy physician and diving medicine and saturation diving researcher
Robert Boyle – Anglo-Irish scientist (1627–1691)
Alf O. Brubakk – Norwegian decompression researcher (1941–2022)
Albert A. Bühlmann – Swiss physician and decompression researcher (1923–1994)
John R. Clarke (scientist) – American scientist and underwater breathing apparatus authority
William Paul Fife – US Air Force officer and hyperbaric medicine researcher
John Scott Haldane – British physiologist and decompression researcher (1860–1936)
Robert William Hamilton Jr. – American physiologist and researcher in hyperbaric physiology.
Leonard Erskine Hill – British physiologist and diving physiology researcher
Brian Andrew Hills – Physiologist who worked on decompression theory
Felix Hoppe-Seyler – German physiologist and chemist (1825–1895)
Christian J. Lambertsen – American environmental and diving medicine specialist
Simon Mitchell – New Zealand physician and author on diving medicine
Charles Momsen – US Navy admiral, submarine rescue (1896–1967)
John Rawlins R.N. – Royal Navy officer and pioneer in the field of diving medicine
Charles Wesley Shilling – U.S. Navy physician, researcher, and educator
Edward D. Thalmann – American hyperbaric medicine specialist and decompression researcher
Jacques Triger – French geologist who invented the pressurised caisson (1801–1867)

Underwater divers

This is a list of underwater divers whose exploits have made them notable. Underwater divers are people who take part in underwater diving activities – Underwater diving is practiced as part of an occupation, or for recreation, where the practitioner submerges below the surface of the water or other liquid for a period which may range between seconds to order of a day at a time, either exposed to the ambient pressure or isolated by a pressure resistant suit, to interact with the underwater environment for pleasure, competitive sport, or as a means to reach a work site for profit or in the pursuit of knowledge, and may use no equipment at all, or a wide range of equipment which may include breathing apparatus, environmental protective clothing, aids to vision, communication, propulsion, maneuverability, buoyancy and safety equipment, and tools for the task at hand. (Full article...)

Outline of underwater divers – Hierarchical outline list of biographical articles about underwater divers
Index of underwater divers – Alphabetical listing of articles about underwater divers

Pioneers of diving

Jacques Cousteau

James F. Cahill – American scuba diving pioneer
Alphonse and Théodore Carmagnolle – French inventors of the first anthropomorphic armoured diving suit
Charles Condert – Inventor of an unsuccessful early scuba system
Jacques Cousteau – Inventor of scuba-diving apparatus and film-maker
Charles Anthony Deane – Pioneering diving engineer and inventor of a surface supplied diving helmet
John Deane – Joint inventor of the diving helmet
Louis de Corlieu – French naval officer and inventor of the swimfin
Guglielmo de Lorena – Italian inventor of a diving bell used for archaeological work on the Roman ships of lake Nemi
Auguste Denayrouze – French inventor of a demand air supply regulator for underwater diving
Frédéric Dumas – French pioneer of scuba diving
Ted Eldred – Australian inventor of the single hose diving regulator
Maurice Fernez – French inventor and pioneer in underwater breathing apparatus
Émile Gagnan – French engineer and co-inventor of the open circuit demand scuba regulator
Bret Gilliam – Pioneering technical diver and author.
Edmond Halley – English astronomer, geophysicist, mathematician, meteorologist, and physicist
Hans Hass – Austrian biologist, film-maker, and underwater diving pioneer
Stig Insulán – Inventor of an adjustable automatic exhaust valve for variable volume dry suits
Jim Jarret – Diver who test dived the first successful atmospheric diving suits
Yves Le Prieur – French naval officer and inventor of a free-flow scuba system
John Lethbridge – English wool merchant who invented a diving machine in 1715
William Hogarth Main – Cave diver and scuba configuration experimentalist
Phil Nuytten – Canadian deep-ocean explorer, scientist, and inventor of the Newtsuit
Joseph Salim Peress – pioneering British diving engineer
Benoît Rouquayrol – French inventor of an early diving demand regulator
Dick Rutkowski – American pioneer in hyperbaric and diving medicine and use of mixed breathing gases for diving
Joe Savoie – Inventor of the neck dam for lightweight helmets
Augustus Siebe – German-born British engineer mostly known for his contributions to diving equipment
Charles Spalding – Scottish confectioner and amateur diving bell designer
Robert Sténuit – Belgian journalist, writer, underwater archeologist and the first aquanaut.
Arne Zetterström – Diver involved in experimental work with Hydrox breathing gas

Underwater art and artists

Christ of the Abyss at San Fruttuoso, Liguria

Jason deCaires Taylor – British sculptor and creator of the world's first underwater sculpture park
Christ of the Abyss – Submerged statue of Jesus Christ

Diving tourism

Dive boat – Boat used for the support of scuba diving operations
- Basic dive boat – Dive boat with minimal facilities
- Day dive boat – Dive boat for longer trips without overnight accommodation
- Liveaboard dive boat – Vessel providing support for diving tourists
Dive guide (publication) – Travel guides for recreational diving
Dive resort – Recreational diving service provider with accommodation
Environmental impact of recreational diving – Effects of scuba diving on the underwater environment
Introductory diving, also known as Resort diving, Try diving – Non-certification scuba diving experience
Recreational diving – Diving for the purpose of leisure and enjoyment, usually when using scuba equipment
Recreational diving service provider – Tangible and intangible goods and services provision for recreational diving tourism
Diver training referral system – System for allowing training to be completed by another instructor
Refresher training – Training to update existing skills and knowledge
Scuba diving tourism – Industry based on recreational diver travel
Shark tourism – Tourism industry based on viewing wild sharks
Sinking ships for wreck diving sites – Scuttling old ships to produce artificial reefs

Awards and events

Hans Hass Award – Award in recognition of contribution made to the advancement of knowledge of the ocean
International Scuba Diving Hall of Fame – Annual event recognizing recreational scuba industry contributors
London Diving Chamber Dive Lectures – Series of public lectures that have been hosted at the Royal Geographical Society in London
NOGI Awards – Annual awards by Academy of Underwater Arts and Sciences.
Women Divers Hall of Fame – International honor society

Terminology

Glossary of underwater diving terminology

References

External links