A device that enables a character to swim underwater without worrying about the OxygenMeter, unless the device runs on air tanks. These are used to find and explore UnderwaterRuins and the UnderwaterCity.

See also SuperNotDrowningSkills. The inverse, which allows an aquatic character to handle non-aquatic environments, is a MobileFishbowl.

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!!Examples:

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[[folder:Anime and Manga]]
* 008 from ''{{Cyborg 009}}'' has this as one of his cybernetic enhancements, as well as other modifications that allow him to survive deep sea pressures, even having most of his skin replaced with metal scales as a MidseasonUpgrade after being blown up. The other cyborgs have built-in oxygen tanks that let them hold their breath longer than a normal person, but 008 is the only one who can actually breathe water.
* Professor Fumble in ''Anime/MarineBoy'' invented "Oxy-Gum," which lets Marine Boy get all the oxygen he needs for hours from simply chewing the gum.
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[[folder:Comic Books]]
* Franchise/{{Batman}} carries a rebreather in his utility belt.
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[[folder:{{Film}} - Live Action]]
* ''Film/{{Thunderball}}''
* ''Franchise/StarWars'' has Rebreathers, used for breathing in hazardous environments, including underwater. A notable example is from ''Film/ThePhantomMenace'', where Qui-Gon and Obi-Wan use them to swim down to the Gungan city.
** On Admiral Ackbar's planet Mon Calamari (seen in ''[[Literature/JediAcademyTrilogy Dark Apprentice]]''), they have flexible, jelly-like breathers you slap over your nose and mouth and it filters the water into oxygen. The Yuuzan Vong in the ''Literature/NewJediOrder'' series have a similar creature called a gnullith that covers the nose and mouth, and extends down the windpipe to interface with the lungs directly. It's incredibly useful, but you might want to find a different solution; it ''hurts like a motherfucker'' because of the Yuuzan-Vong's cultural obsession with pain.
* ''Film/TheAbyss'' had a gooey gel that was hyperoxygenated for super deep sea diving. [[TruthInTelevision This is a real thing]]. The scene with the rat was a real rat really being held under the surface of the liquid and freaking out because it had no idea what was going on. Animal welfare groups were annoyed about it because they thought it was being put in unnecessary distress.
* At the end of ''Film/SherlockHolmesAGameOfShadows'', [[spoiler:Watson receives Mycroft's oxygen inhaler in a parcel sent by Holmes, who stole the inhaler from his brother and used it to survive when he pulled Moriarty down the Reichenbach falls with him.]]
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[[folder:{{Literature}}]]
* ''Literature/HarryPotterAndTheGobletOfFire'' introduces gillyweed, a plant that when consumed causes the eater to temporarily grow gills. Another option is the Bubble-Head Charm, which surrounds the subject's head in a bubble of air to let them breathe normally.
* Literature/DocSavage not only had diving suits more advanced than anything available in RealLife at the time, but also 'oxygen tablets' that supplied oxygen directly to the blood and allowed the users to survive underwater for about two hours.
* In ''Literature/DarkLife'', there is liquid oxygen that allows people to live underwater.
* PoulAnderson's fantasy novel ''Three Hearts and Three Lions'' sees the hero, Holger Carlsen, abducted by a ''nixie'' (a freshwater mermaid - think Rheinmaidens in Wagner opera). She confers on him the gift of being able to live and breathe underwater, but capriciously cancels his artificial gill when he declines her kind offer to live with her underwater forever.
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[[folder: Live Action TV]]
* ''Series/BabylonFive''. Several races need to use breathers when going into the alien sector and several alien races need to use breathers to travel the rest of the station. Also, G'Kar has gills surgically added that allow him to breathe in alien atmospheres without a device. Lyta gets a set after being TouchedByVorlons.
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[[folder:Tabletop Games]]
* Early editions of ''TabletopGame/DungeonsAndDragons''
** A number of magical items had this ability, such as the Helm of Underwater Action, the Cloak of the Manta Ray, Potions of Water Breathing, the Necklace of Adaptation and the Ring of Water Adaptation.
** Spells: the Airy Water and Water Breathing spells.
** "Natural" magic items: module [=EX1=] ''Dungeonland'' had seaweed that allowed breathing underwater. There were similar items in other adventures.
* The artificial gill and the gill suit from ''TabletopGame/{{GURPS}}: Ultra-Tech'' allow people to spend hours or even days underwater. In ''High-Tech'' SCUBA and rebreather gear is available. Even as far back in time as ''Low-Tech'' it's possible to get waterproofed animal skins that give a few extra breaths if used correctly.
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[[folder:{{Toys}}]]
* ''Franchise/{{BIONICLE}}'': the [[MaskPower Kaukau and Kaukau Nuva]], a.k.a. the Masks of Water Breathing. These filter oxygen out of the water and allow the wearer to breathe.
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[[folder:Video Games]]
* Mario gets one for the Literal Bottle levels in ''VideoGame/SuperMarioSunshine''. It extends the time he can breathe underwater without grabbing coins.
* ''Franchise/TheLegendOfZelda'' series has many items that serve this function:
** Zora's Flippers appear in many of the 2D games, and sometimes allow Link to breathe underwater. Other times, they only allow him to swim in deep water and still require him to come up for air periodically.
** ''VideoGame/TheLegendOfZeldaOcarinaOfTime'' has the Zora Tunic that lets Link breathe underwater.
** ''[[VideoGame/TheLegendOfZeldaOracleGames Oracle Of Ages]]'' has the Mermaid suit.
*** Both ''Ages'' and ''Seasons'' also have the Zora Ring, which allows you to stay submerged in shallow water for as long as you want.
** ''[[VideoGame/TheLegendOfZeldaTwilightPrincess Twilight Princess]]'' has the Zora Armor. When Link is underwater, a small mask covers his nose and mouth, letting him breathe underwater.
* ''VideoGame/CommanderKeen 4'' has a set of scuba gear, but it has an unlimited air supply.
* Oxyale in ''VideoGame/FinalFantasyI''
** ''VideoGame/FinalFantasyVI'' had the diving helmet, which enables Sabin, Cyan, and Gau to travel the underwater Serpent Trench back to Narshe. [[FridgeLogic With a single diving helmet. For three of them.]]
** The underwater materia in ''VideoGame/FinalFantasyVII''
* The Aqualung item in ''AlterAILAGenesis''. You actually can't go underwater at ''all'' until you get it. Also lampshaded when it's obtained, as the character that normally explains these kinds of things says she has no idea how it works.
* Variation; it's a spell in ''Videogame/{{MARDEK}}'' that can only be cast by a specific party member. A straighter example would be the Oxyale, a consumable potion that bestows the same effect.
* ''VideoGame/Sonic3AndKnuckles'' featured the bubble shield, which bestowed SuperNotDrowningSkills.
** Knuckles picks up the Air Necklace as one of his power-ups in ''VideoGame/SonicAdventure2'', allowing him to stay under indefinitely.
* In ''VideoGame/CaveStory'', Curly Brace has an air tank... which makes the player character's susceptibility to drowning all the more frustrating. She eventually gives you the air tank.
* ''VideoGame/DukeNukem3D'' has a scuba gear pickup which lets the player spend several minutes underwater, as opposed to maybe 30 seconds without it.
* A signature item in the Build engine games. ''Duke Nukem 3D'', ''RendeckRampage'', and ''Videogame/{{Blood}}'' all have it.
* ''VideoGame/WorldOfWarcraft'' makes extensive use of this trope:
** Class-specific spells; druid Aquatic Form, warlock Unending Breath, and shaman Water Breathing.
** Crafting provide water breathing potions and the Deepdive Helmet created by engineering.
** A weapon from Gnomeregan also functions as an Artificial Gill.
** As a whole, Blizzard learned during ''Wrath of the Lich King'' that underwater quests were a pain in the ass and most such quests now provide a renewable Artificial Gill buff. ''Cataclysm'' adds the game's first underwater zone, Vashj'ir, and the first couple of quests are to gain a permanent, zone-only Artificial Gill that also provides substantially faster swim speed, without which Vashj'ir would be all but unplayable.
* In ''ManaKhemia2FallOfAlchemy'', the access to Deep Sea Ruins is opened after you synthesize Air Drop. Said item also returns in ''VideoGame/{{Atelier Rorona|The Alchemist Of Arland}}''
* Later games in ''Franchise/TheElderScrolls'' series have spells and enchantments for this available to players.
* On the Online Games by Artix Entertainment, it is finally explained why you can breathe underwater in all 5 games.
* In ''Dragon Fable'', you sink a ship full of water breathing potions that contaminates and enchants the ocean so that you can breathe underwater.
* ''Franchise/BreathOfFire'':
** ''VideoGame/BreathOfFireI'' required you to find a gill key item to let any character other than Gobi (a fishman) travel underwater.
** ''VideoGame/BreathOfFireII'' featured such an item as well.
* ''VideoGame/FalloutNewVegas'' gives you a rebreather if you help the Boomers, but other than a related mission and two caves there is absolutely nothing to see in the depths of Lake Mead. However there are certain areas of Vaults that happen to be submerged.
* In the ''VideoGame/KingsQuestII'' fan remake, a mermaid gives King Graham a kiss that somehow lets him breathe underwater.
* ''VideoGame/{{Unreal}}'' has SCUBA gears available whenever the player must proceed underwater. They have a limited air supply that runs out pretty quickly. The expansion pack features a new one that not only lasts longer, but also recharges whenever surfaced.
** The SCUBA Gear reappears in the Oceanfloor assault map in ''VideoGame/UnrealTournament''.
* ''{{VideoGame/Terraria}}'' has an accessory that allows for underwater breathing.
** There's also a Gills potion, which [[ExactlyWhatItSaysOnTheTin makes you grow gills]]. Also lacks the RequiredSecondaryPower of your lungs working normally alongside it, making you suffocate outside of water unless you wear a water-filled Fish Bowl on your head [[FridgeBrilliance which normally suffocates you since there's water inside it.]]
* ''{{Wizard 101}}'' has underwater breathing potions early in the game to allow access to a street that is completely underwater. However, due to the game mechanics, players can teleport to this area without adverse effects.
** Later there is a device in Celestia that allows the player to breathe in the underwater areas. It was designed by the [[{{Precursors}} Celestians]] to survive when the [[WildCard Storm Titan]] betrayed them and flooded their world. [[YouAreTooLate Too bad they finished it too late.]]
* ''VideoGame/DeusEx'' has [[http://deusex.wikia.com/wiki/Rebreather rebreathers]] that allow you to breathe underwater for a limited time. The [[VideoGame/DeusExHumanRevolution prequel]] features an [[http://deusex.wikia.com/wiki/Augmentations_%28DX3%29#Implanted_Rebreather Implanted Rebreather]] that does the same for poisonous gases but not water (or at least we don't see it do so, because you never go underwater).
* In ''GuildWars2'' every character has one standard, because the dev team did not want to limit the underwater areas' size to how long you could hold your breath.
* The leaves of the Maurera Tree in ''VideoGame/PhantasyStarII'' can be refined into special chewing gum to provide oxygen while travelling underwater; this is used to reach Climatrol.
* The Survival System backpack in ''VideoGame/{{Starbound}}'' allows one to breathe indefinitely underwater, as well as in space.
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[[folder:Western Animation]]
* In ''WesternAnimation/TheSimpsons'' Bart once used Milhouse's inhaler as a breathing device.
* ''WesternAnimation/SamuraiJack'': Jack is given a device to help him breathe underwater while swimming to the submerged HumongousMecha.
* The animated ''WesternAnimation/FlashGordon'' had an episode with featuring a literal ArtificialGill: It was a metal collar with gills, that also prevented the wearer from breathing outside of water.
* ''WesternAnimation/KimPossible'' uses a rebreather provided by Wade in an episode where Drakken seals her in a filled-with-water bottomless pit.
* ''WesternAnimation/{{Futurama}}'': The crew is given rebreathers when they find the lost city of Atlanta.
** And [[ToiletHumor suppos]][[AssShove itories]] to help them with the pressure.
* The Gills of Hamachi from ''WesternAnimation/XiaolinShowdown'', although it achieves this by turning the user into a literal fish person.
* In ''WesternAnimation/YoungJustice'', Robin I/ Nightwing carries these as part of his standard equipment. After three missions in a row nearly lead Artemis to drowning, she starts to carry them, too.
** At some point between seasons 1 and 2, they were regularly stocked on board the bio-ship. Lagoon Boy seriously messes up when he forgets to replenish them for a mission.
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[[folder:RealLife]]
* Underwater gear generally falls into two categories, tanks of compressed air, and rebreathers. The former exhales directly into the water (leading to the characteristic bubbles), while the latter simply filters out the [=CO2=] and adds oxygen so the nitrogen can be re-used. It still has some gas, so it's only a partial example.
* Mosquito larvae have a biological snorkel that they use to breathe from just below the surface of the water. All aquatic snails also have snorkels.
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