AskDefine | Define frogman

Dictionary Definition

frogman n : someone who works underwater [syn: diver, underwater diver]

User Contributed Dictionary



  1. A diver, especially one in a diving suit (as opposed to one in scuba gear).
  2. A US Navy SEAL.



Extensive Definition

This page describes a type of scuba diver. For other uses of the word frogman, see Frogman (disambiguation)
The term frogman refers to military personnel who are trained to dive or swim in a military capacity, often in combat. Such personnel are also known by the more formal names of combat diver or combat swimmer. Strictly speaking, "combat swimming" refers to surface swimming without a breathing apparatus for the purposes of coastal or ship infiltration, which is a traditional form of "frogman" activity and is thus an important feature of naval special operations. In popular usage, the term '"frogman" might also refer to a civilian scuba diver. The word arose around 1940 from the appearance of a diver in shiny wetsuit and large fins. Though the preferred term by scuba users is "diver", the "frogman" epithet persists in informal usage by non-divers, especially in the media and often in reference to professional scuba divers such as in a police role. Also, some sport diving clubs include the word "Frogmen" in their names.
In the US Military, divers trained in scuba or CCUBA who deploy for military assault missions are called "combat swimmers". This term is used to refer to the Navy SEALs, the Marine Recon swimmers, the Army Ranger swimmers, and the Navy Explosive Ordnance Disposal (EOD) units.
In Britain, police divers have often been called "police frogmen". The first British police diver was a policeman who, needing to search underwater for evidence or a body, did not use a drag but went home and fetched his sport scuba gear. See also Ian Edward Fraser.
Some countries' frogman organizations include a translation of the word "frogman" in their official names, e.g. Denmark's "Frømandskorpset" and Norway's "Froskemanskorpset"; others call themselves "combat divers" or similar. Others call themselves by indefinite names such as "special group 13" and "special operations unit".
Many nations and some irregular armed groups deploy or have deployed combat frogmen.

Defending against frogmen

Types of armed-forces divers

Military diving is a branch of professional diving carried out by armed forces. They may be divided into:
  • Combat / assault divers.
  • Armed forces work divers (called Clearance Divers in the Royal Navy and Royal Australian Navy), who do general work underwater.
  • Armed forces work divers who are trained in defusing mines and removing other explosives underwater.
These groups may overlap, and the same men may serve as assault divers and work divers, as in the Australian Clearance Diving Team (RAN).

Frogman training

Training armed forces divers, including combat divers, is far harder, longer, and more complicated than civilian sport scuba diver training, typically takes several weeks full-time, and the trainees must be at full armed forces fitness and discipline at the start. It needs much higher levels of fitness, and during the course there is often a high elimination rate of trainees who do not make the grade. For more details see the articles on each nation's frogman group below and their external links.
This contrasts with civilian sport scuba diving training which tends to be one evening a week, being 30 to 60 minutes swimming pool time, followed by two hours or so of dry meeting (often in a social-club-type environment with an open bar). The general environment at sport dives is liable to encourage what a naval diver-trainer would call "a casual tourist-type attitude to being underwater", rather than a disciplined attitude of obeying orders and not being distracted; some naval diver-trainers prefer, or will only accept, trainees who have no previous scuba diving experience.
For example, the PADI Open Water Diver (the most basic rank) course takes 5 dives in a swimming pool and 4 dives in open water (i.e. sea, lake, etc.); after the course the qualified diver is allowed to dive to 18 meters = 59 feet depth. The next step (Advanced Open Water Diver) allows him to dive to 30 meters (100 feet). A further Deep Diver Speciality course allows him to dive to 40 meters (130 feet) maximum, which is considered safe for civil scuba diving: 30 m is recommended as the normal maximum. This can be compared with military frogman training courses as described in some of the articles about national military frogman bodies included or pointed to below, and their included external links.


Breathing sets

Frogmen's breathing sets on covert operations should have particular features.
  • Some are needed because they may need to swim fast and far.
  • Some are needed to avoid detection.
  • Sometimes patrol divers may have to be sent down to find or arrest submerged suspect divers. For reasons stated in Anti-frogman techniques#Sending other frogmen against them, underwater fights between divers are much rarer in reality than in fiction, and thus suitability of the frogman's kit for "diver to diver combat" is less important than some other features when designing it; but the point is considered here for completeness.
USA frogmen's rebreathers tended to have the breathing bag on the back before enclosed backpack-box rebreathers became common.

Features needed

A frogman's breathing set should:
  • Be as silent as possible in use.
  • Have a full face diving mask:
      • To let frogmen communicate underwater.
      • It is less easily knocked off underwater.
      • It is much less easily lost if the frogman goes unconscious underwater.
    • And see here. It should have as little as possible (e.g. an excessively bulky or projecting set/air valve) that can catch on things or that an attacker could easily grasp.
  • Be a dull color to avoid being seen from out of the water. Many are black, but the Russian IDA71's backpack box is mostly dark green. No large bright-colored badges or manufacturer's logos.
  • Contain as little iron or steel as possible, to avoid detection by magnetic sensors. This is also useful when the frogmen have to remove or defuse mines underwater.
  • Be as light and agile as possible, as far as is compatible with an adequate dive duration:
    • Be well streamlined, and as small and light as possible for the dive duration. With a combat diver this may mean removing safety features such as an open-circuit bailout that would add bulk. Long trailing hoses (e.g. regulator hoses) are easily fouled and or pulled at and add to drag. If an underwater fight, or a quick need to escape, develops, agility and lack of cumbersomeness could be vital. This applies to:
  • Have a long dive duration.
  • The front of the frogman's abdomen should be clear so he can easily climb in and out of small boats or over obstacles, particularly out of the water.
  • Its breathing bag should be toughened against stabbing and scratches, or safely inside a hard backpack box.
  • All controls should be where the frogman can easily reach them, and not projecting. Turning the usual type of sport diving scuba's air off or on is easy for an attacker from above but difficult or impossible for the diver himself (and has been known to happen by itself when a diver pushes through thick kelp), unless the cylinder or cylinders are mounted inverted. However, that needs more pipework, and it is easy to bump the valvework on things, including when taking the set off.
  • Its working parts and breathing tube or tubes should be safe from snagging on things in dark water, and from attack in an underwater fight, including in the risk of being "jumped" from above.
    • Long trailing breathing tubes or regulator hoses may snag on things in dark water and can easily be grasped and pulled.
    • Older Siebe Gorman-type rebreathers (see Siebe Gorman CDBA) had one breathing tube, which was in front of the chest and easier for the frogman to keep track of.

Not open-circuit scuba

As a result, the frogman's breathing set should be fully closed circuit rebreather, preferably not semi-closed circuit and certainly not open-circuit scuba, because:
  • Open-circuit scuba makes large amounts of bubbles, showing where the diver is.
  • Open-circuit scuba makes noise (on exhalation, and regulator valve intake hiss as the diver breathes in) showing underwater listening devices where the diver is.
    • There have been experiments with making released air or gas come out through a diffuser, to break the bubbles up; this may sometimes work with the small amounts of gas that are sometimes released by rebreathers, but open-circuit scuba releases so much gas at every breath that a diffuser large enough to handle it without making breathing difficult would be too bulky and would interfere with streamlining. Holding the breath to avoid making noise at critical moments is not recommended and very risky: see diving hazards and precautions
  • The bulk of an open-circuit set makes the diver heavy and cumbersome in rolling over and changing course or speed.
  • The dive duration of open circuit sets is much shorter than the dive duration of naval rebreathers, in proportion to bulk. However, some "technical diving" rebreathers are very burdened with safety devices such as inflatable flotation and open-circuit bailout. (Some modern rebreathers, such as the Draeger, are lighter.) The rebreathers which are the most compact in proportion to dive duration are oxygen rebreathers, which are depth limited to about 8 meters = 26 feet due to the oxygen toxicity risk.
  • The common sport open-circuit scuba set is not recommended for a fight against a trained naval or combat diver, because in any sort of underwater combat, a man with a large aqualung has a high rotation-inertia and is very unstreamlined in the twisting and turning involved in fighting and straight swimming, and his maneuvering is slowed critically compared to a man with a light streamlined rebreather with all parts close to his body.
Combat frogmen sometimes use open-circuit scuba sets during training and for operations where being detected or long distance swimming are not significant concerns.

The Russian IDA71

The Russian IDA71 military and naval rebreather is a typical frogman set:
  • Its working parts are in a hard smooth rounded metal backpack casing which has little that can snag on things or be easily grasped and pulled at. There is no mass of projecting valvework behind his neck to cause hydrodynamic drag and for an attacker to grasp.
  • Its only external control is its on/off switch, which is on its right edge near the bottom where he can reach it easily, and does not stick out.
  • It does have looping breathing tubes like an old-type aqualung, but these originate well apart next to where they come over his shoulders and do not have to reach across from the back of his neck. They can be strapped to the shoulder straps so they do not float up into big vulnerable loops behind the shoulders.
  • When the frogman comes out of water quickly, the holes in the casing let contained water drain quickly, so he is quickly rid of the weight of that water.
  • In oxygen rebreather mode it is said to last 4 hours on a filling.


Most frogmen use a full face diving mask instead of separate mouthpiece and mask. The older type of British frogman's and naval diving mask was full face and had a mouthpiece inside it. Some frogmen use a mouthpiece and noseclip or a mouth-and-nose (oro-nasal) breathing mask instead of a diving mask with eye windows, and special contact lenses to correct the vision refraction error caused by the eyeballs being directly submerged. This is to avoid a searchlight or other lights reflecting off the mask window and thus revealing his presence, but it exposes the eyeballs to any pollution, poison, or organisms in the water.
The United States military has adopted Oceanic/Aeris's "Integrated Diver Display Mask". It is a basic "Heads-Up Display" that lets divers monitor depth, bottom time, tank pressures, and related information while leaving their hands free for other tasks.


Another problem with a frogman who may have to come ashore and operate on land is the awkwardness of walking on land in fins, unless he plans to discard his kit and return to base by some other way than by diving, or if the frogmen plan to take and hold a position on land until other troops arrive. Some sport diving fins have the blade angled downwards for more effective swimming, but this makes walking on them more awkward.
The usual solution is for the frogman to take his fins off and carry them, but that takes time and occupies a hand carrying them unless he can clip them in to his kit or thread an arm through the fins' straps.
Another type of fin that frogmen could use would have a lockable hinge which on land can be unlocked to let the fin blade hinge up out of the way when walking.
The first type of British naval swimming fin had a short blade which was even shorter at the big toe side: this made walking on land easier for such purposes as creeping up on a sentry from behind on land, but reduced swimming speed.

Diving suits

The frogman's diving suit should be a tough scratch-and-cut-resistant drysuit (perhaps reinforced with kevlar), and not a soft foam wetsuit. A wetsuit can be worn under the drysuit as a warm undersuit. In very warm water, a thin tough drysuit can be worn with no undersuit.
  • For Bomb Disposal Operations, Canadian Naval Divers wear Bomb suits.
It should not have obvious bright colored patches, unit badges or the suit's maker's advertising. Diving sea-police types, however, may find that a unit badge is useful.

Tools and weapons carried underwater

Weapons that can be carried by a frogman include:

Transport for frogmen

Frogmen may approach their site of operation and return to base in various ways including: General Purpose Boat FDU(P),Yard Diving Tender (YDT) Sooke,and the YDT 11 FDU(P).
  • The Subskimmer and similar.
  • Midget submarines such as the X-craft, the SDV or the US Advanced SEAL Delivery System ASDS which frogmen can exit and return to through an airlock.
  • Full-sized submarines which frogmen can exit and return to, sometimes through a special airlock or through one of the sub's torpedo tubes. These two methods, like all methods, need precautions: this link (in Russian) describes a risky incident in diving from a submerged submarine: the sub was neutrally buoyant at the start, and the first frogman airlocking changed the sub's buoyancy, and the sub started to float up; in later dives the sub's captain ballasted the sub well to keep the sub on the seabed while frogmen were coming out or in.
  • More powerful versions of sport-diving diver-tugs. Unmodified sport-diving diver-tugs are usually not powerful enough or not long enough duration on a battery recharging.
  • The Protei 5 and similar. See Diver Propulsion Vehicle.
  • Some frogmen are trained to parachute in to their site of operation. The backpack box of the Russian IDA71 frogman's rebreather has two metal clips to fasten to a parachute harness.

Types of frogman operations

  • Amphibious assault: stealthy deployment of land or boarding forces. The vast majority of Combat Swimmer missions are simply to get "from here to there" and arrive suitably equipped and in sufficient physical condition to fight on arrival. The deployment of tactical forces using the arrival by water to assault land targets, drilling platforms, or surface ship targets (as in boardings for seizure of evidence), is a major driver behind the equipping and training of combat swimmers. The purposes are many, but include feint and deception, anti-drug, law enforcement, anti-terrorism, and anti-proliferation missions.
  • Sabotage: This includes putting limpet mines on ships.
  • Clandestine surveying: Surveying a beach before a troop landing, or other forms of unauthorized underwater surveying in denied waters. The article "Riding on Proton" by Afonchenko (in Russian) may describe in passing a Soviet Bloc frogman infiltration into South Korean sea.
  • Clandestine underwater work, e.g.:
    • Recovering underwater objects.
    • Clandestine fitting of monitoring devices on underwater communication cables in enemy waters.
  • Investigating unidentified divers, or a sonar echo that may be unidentified divers. Diving sea-police work may be included here. See anti-frogman techniques.
  • Checking ships, boats, structures, and harbors for limpet mines and other sabotage; and ordinary routine maintenance in war conditions. If the inspection divers during this find attacking frogmen laying mines, this category may merge into the previous category.
  • Underwater mine clearance and bomb disposal.

Mission descriptions

The U.S. and UK forces use these official definitions for mission descriptors:
  • Stealthy - Keeping out of sight (e.g. underwater) when approaching the target.
  • Covert - Carrying out an action which the enemy may become aware of, but it cannot easily be discovered who or what did it. Covert action often involves military force which cannot be hidden once it has happened. Stealth on approach, and frequently on departure, may be used.
  • Clandestine - It is intended that the enemy does not find out then or afterwards that the action has happened. Installing eavesdropping devices is the best example. Approach, installing the devices, and departure are all to be kept from the knowledge of the enemy. If the operation or its purpose is exposed, then the actor will usually make sure that the action at least remains "covert", or unattributable: e.g. ("...the secretary will disavow any knowledge of your actions.")

Derivative word usages

  • Some scuba diving clubs have an entry class called "Tadpoles" for younger children who want to start scuba diving.
  • Royal Navy men have a slang term "pond life" to mean civilian sport divers.

Errors about frogmen found in public media

Wrong use of the word "frogman"

A new English translation of the book Twenty Thousand Leagues Under the Sea uses the word "frogman" uniformly and wrongly to mean a diver in standard diving dress or similar, to translate French scaphandrier.

Supposed ancient scuba divers/frogmen

Ancient Assyrian stone carvings show images which some have supposed to be frogmen with crude breathing sets. However, the "breathing set" was merely a goatskin float used to cross a river, and its "breathing tube" was to inflate it by mouth. See timeline of underwater technology.

Mistakes in fiction


Many comics have depicted combat frogmen and other covert divers using two-cylinder twin-hose open-circuit aqualungs. All real covert frogmen use rebreathers because the stream of bubbles from an open-circuit set would give away the diver.
Many aqualungs have been anachronistically depicted in comics in stories set during World War II, when in reality aqualungs were unknown outside Jacques-Yves Cousteau and his close associates in Toulon in south France. Some aqualungs were smuggled out of occupied France during the war (these may have been Commeinhes aqualungs), but the aqualung for the most part was not a player in combat in World War II.
The movie The Frogmen also made this mistake, using three-cylindered aqualungs, as in this image of a movie poster. DESCO were making three-cylinder constant flow sets that lacked the demand valve of the aqualung, but they were rarely deployed in the war, and the preferred system was the rebreather developed by Dr. Christian J. Lambertsen.
Ian Edward Fraser V.C. in 1957 wrote a book Frogman V.C. about his experiences. Whoever designed its dust cover depicted a frogman placing a limpet mine on a ship, wearing a breathing set with twin over-the-shoulder wide breathing tubes emitting bubbles from behind his neck, presumably drawn after an old-type aqualung.

Drawing and artwork

There have been thousands of drawings (mostly in comics, some elsewhere) of combat frogmen and other scuba divers with two-cylinder twin-hose aqualungs shown wrongly with one wide breathing tube coming straight out of each cylinder top with no regulator, far more than of twin-hose aqualungs drawn correctly with a regulator, or of combat frogmen with rebreathers. See this image for the correct layout of an old-type aqualung.
This recent painting or CGI-type image on a website advertising the CSDS-85 frogman-detector sonar shows (bottom left corner) a frogman using open-circuit scuba complete with bubbles carrying a flying-saucer-shaped object which is likely meant to be a limpet mine.

Movies and fiction

Frogman-type operations have featured in many comics, books, and movies. Some try to reconstruct real events; others are completely fictional. Some make mistakes as described above. Examples are:


In ancient Roman and Greek times, etc, there were many instances of men swimming or diving for combat, but they always had to hold their breath, and had no diving equipment, except sometimes a hollow plant stem used as a snorkel. See the first part of the page at this link (in Portuguese).
The first known frogmen-type operations using breathing apparatus were by the Italian Decima Flottiglia MAS, which formed in 1938 and was in action first in 1940. See Timeline of underwater technology and each of the nations' frogman unit links below.

Nations with military diving groups

Italy started World War II with a commando frogman force already trained. Britain, Germany, the United States, and the Soviet Union started commando frogman forces during World War II.


The Buzos Tácticos is Argentina's combat frogmen force.



The Clearance Diving Team (RAN) is Australia's combat frogman and underwater work force.





During Eritrea's war of independence against Ethiopia, the rebel forces had a combat frogman force. After the war, some of those frogman were retrained as dive guides for the sport scuba diving tourism trade.


The Finnish Navy has trained Finnish combat divers since 1954. Conscripts and career military are eligible to apply for the training. Annually about 20 conscripts are trained for diving duties. Applying for combat diver training is voluntary, and the selection criteria are stringent. The conscript divers are trained either for anti-mine or for commando operations while career personnel may also be trained for deep-sea diving duty. All conscript divers receive at least NCO training during their 12-month service period.




The MCU is the elite naval special operations unit of the Indian Navy that undertakes underwater combat.


The TNI-AL/Indonesian Navy Underwater Combat Unit is called Kopaska.


It is reported that Israel's combat frogmen are among the most effective compared to their numbers and are said to have been in many operations. They started in 1948. See Shayetet 13.



Malaysia has a special-forces naval unit called Paskal. It includes frogmen.



The Netherlands's Amphibious Reconnaissance Platoon is part of the Special Forces unit of the Royal Netherlands Marine Corps.

New Zealand

The New Zealand Navy trains all NZ Army, NZ Police, and NZ Customs divers. Military Dive Training support is also supplied to Singapore, Malaysia, Fiji, Tonga, and Samoa.


Norway's commando frogmen corps is called Marinejegerkommandoen = "the naval ranger command" which is something like the British SBS.
Norway has a clearance diver group called Minedykkerkommandoen = "the mine diver command".


Pakistan Army's SSG also has a unit in the Pakistan Navy modeled on the USA Navy SEALs: NSSG, otherwise known as SSGN. The SSGN currently has a headquarters in Karachi headed by Pakistan Navy Commander. It has a strength of one company and is assigned to unconventional warfare operations in the coastal regions. During war it is assigned to Midget submarines. All other training is similar to the Army SSG with specific marine oriented inputs provided at its Headquarters.



Three Polish military divisions train and deploy frogmen in military operations. Most known are GROM water operations division, 1st special commando regiment and Special Operations Section of Polish Navy - Formoza. Polish frogmen operators are confirmed to use these weapons:
  • WIST 94 9 mm pistol
  • H&K USP 9 mm pistol
  • H&K MP-5, MP-5SD 9 mm sub-machine gun
  • Pm-84P Glauberyt 9 mm sub-machine gun
  • PKM/PKSM 7.62 mm sub-machine gun
  • Beryl 5.56 mm assault rifle
  • AKM 7.62 mm assault rifle
The Polish army uses French OXY-NG2 closed-circuit apparatus.





South Africa


Spain has been training combat divers and swimmers since 1967. Two units in the Spanish Navy currently operate under a Naval Special Warfare mandate:
  • UOE (Special Operations Unit) - All aspects of maritime special operations at sea, on land, and by air.
  • UEBC (Specialist Combat Diver Unit) - Mainly hydrographic surveys and underwater demolitions.
There are working plans to fuse the two units into a single "Naval Special Warfare Unit" (UGNE), while maintaining their functional distinctiveness.


  • The Reconnaissance Platoon, also referred to colloquially as the Attack Divers (A-dyk). They conduct long range reconnaissance missions behind enemy lines, sabotage, clearing beach obstacles, hydrographic surveys, and although combat is not their priority, they have a limited ability to conduct direct action missions such as ambushes. Between 6 and 10 are trained each year. The Reconnaissance Platoon is a commando unit, belonging to the amphibious battalion of the Swedish Navy. They offer one of the hardest and most demanding training regimens in the Swedish armed forces.
  • Navy EOD-divers (Röjdyk)
  • Army divers (FArb-dykare) Underwater welding, obstacle clearence, underwater demolition and repairs. Belongs to the engineer troops.
  • Pioneer divers (Pionjärdyk) of the amphibious battalion. Underwater obstacle clearance, repairs and EOD on land.
  • Navy attack divers. (Flottan A-dyk) Underwater sabotage on enemy ships and harbours. The unit was disbanded in 1979.

Tamil Eelam

The Sea Tigers (sea branch of the Tamil Tigers in Sri Lanka) have frogmen for suicide runs.


Underwater search and Finding Commership is the unit gives diving services in Turkey. Also it give deepwater diving and mine diving lessons to officers and petty officers. They become 1. Class Divers. Su Altı Taaruz commandos are high level divers.

United States


frogman in Old English (ca. 450-1100): Froggamann
frogman in Arabic: ضفادع بشرية
frogman in Czech: Žabí muži
frogman in German: Kampfschwimmer
frogman in French: Nageur de combat
frogman in Italian: Sommozzatore
frogman in Japanese: カエル男
frogman in Norwegian: Kampsvømmere
frogman in Russian: Боевые пловцы
frogman in Swedish: Attackdykare
frogman in Chinese: 蛙人

Synonyms, Antonyms and Related Words

Naval Reservist, Royal Marine, Seabee, bather, bathing beauty, bathing girl, bluejacket, boot, cadet, deep-sea diver, diver, free diver, gob, horse marine, jolly, jumper, marine, mermaid, merman, midshipman, midshipmite, natator, naval cadet, navy man, parachute jumper, pearl diver, plunger, scuba diver, skin diver, sky diver, snorkel diver, swabbie, swimmer
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