Oxygen Meter

aka: Ordinary Drowning Skills

"There's some pretty cool stuff down there. Grab a blue balloon and double your dive time, dude!"

— Funky Kong, Donkey Kong Country: Tropical Freeze

Somewhere in between Super Drowning Skills and Super Not-Drowning Skills lies the Oxygen Meter, which indicates the Player Character's capacity to hold their breath. If the Oxygen Meter depletes, one of two things will happen: instant death by asphyxiation or the player character's actual health will begin to drain.

In water levels, there will often be designated stops that allow for the oxygen meter to be refilled, such as ceiling vents that allow you to resurface and breathe or bubbles that pop up in certain places to automatically refill the meter.

Frustratingly, your oxygen meter is sometimes invisible yet still just as real and waiting to bite you; this is most likely to happen in a First-Person Shooter. This is probably just because the interface is already full and they don't want to waste space on something not even used in most levels... and surprisingly, not all games decided to only make it visible when in use.

It's worth noting that dying from lack of oxygen is often played unnervingly straight even in games where deaths are otherwise cartoonish or even Played for Laughs.

The Oxygen Meter may be removed entirely if your character can somehow breathe underwater (through some sort of ability or equipment, or even just being native to water) or doesn't even need to breathe at all (if you're playing as a robot, for example).

An occasional alternative to the Oxygen Meter is to allow only for a finite amount of time underwater before the player character automatically floats back to the surface unharmed—however, this also places a restriction on level design, to avoid the player getting stuck should their "swim timer" run out in the middle of, say, an underwater tunnel or cavern with no air on the surface.

A third way, of course, is to just prohibit underwater travel entirely—either by limiting swimming mechanics to the water's surface (such as in Bully), using Super Drowning Skills, or by simply not allowing the player to interact with deep water in the first place using Invisible Walls. Sure, you can still splash around in puddles and knee-high streams, but to go jump in a lake? Are you crazy?

Games that include a Sprint Meter will often replace it with the Oxygen Meter underwater (or use the same meter for both purposes), since actions that use the Sprint Meter are typically unavailable while swimming.

Characters with Super Not-Drowning Skills, by definition, rarely have need of an Oxygen Meter.

Sub-Trope of Status Line (a display element showing the current disposition of the player, e.g. score, health, ammo, etc).

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Examples:

Adventure

• Grand Theft Auto:
  • Grand Theft Auto: San Andreas. This was a departure from the rest of the series, as previous games gave the player Super Drowning Skills.
  • The game after this, Grand Theft Auto IV, kept the ability to swim but restricts it to the surface, so there's no meter.
  • Grand Theft Auto: Vice City Stories also restricted it to the surface, but added a stamina meter which works exactly as an Oxygen Meter; when it runs out, you're screwed.
  • And then along came Grand Theft Auto V which vastly expanded the underwater world, reintroduced the oxygen meter, and added scuba-diving and controllable submarines which allows the player to explore for longer.
• American McGee's Alice has this meter for underwater levels where you don't have a shell. Annoying in that the meter is not visible, so you must gauge by bubbles when you're almost out of air. Doubly annoying in that once your health begins to decline, you are given absolutely no time to find an air source to stop yourself from dying.
• In Another World, a meter isn't explicitly shown, but as Lester spends time in the water, he releases more and more air bubbles. When the bubbles start getting out more frequently, he'd better be close to the surface.
• In Shadow of the Colossus, your stamina meter doubled as an oxygen meter. If it ran out, you would simply let go of whatever you were holding and return to the surface. Because the two are the same, it makes it rather odd when the main character is panting and gasping while completely submerged in the water.
• The 3D The Legend of Zelda games use both varieties:
  • The Legend of Zelda: Ocarina of Time: Diving while swimming normally only lasts for a few seconds before Link resurfaces (in the former game, the Silver Scale raises the timer to 6, and the Golden Scale does for 8). Equipping the Iron Boots in the former game lets Link stay underwater longer, in which case a timer based on how much health you have appears (unless you also equip the Zora Tunic, which lets you breathe underwater). These two items are important in the Water Temple.
  • The Legend of Zelda: Majora's Mask: Link's timer while diving is only two seconds. Fortunately, Link wearing the Zora Mask will eliminate the swimming restrictions.
  • The Legend of Zelda: The Wind Waker does not have any underwater breathing, but does have a stamina bar to prevent you from swimming from island to island (which can only be done by sailing your boat). This also applies to The Legend of Zelda: Breath of the Wild, in which Link can only swim on the surface and while the standard Sprint Meter lasts.
  • The Legend of Zelda: Twilight Princess has a blue bar that appears whenever Link is sunken underwater with the Iron Boots. Once again, wearing the Zora Armor will allow him to swim for as long as he wants.
  • The Legend of Zelda: Skyward Sword has an oxygen meter as well, which is barely of note until you get the Water Dragon's Scale (Link automatically floats upward when he's not focused on swimming). It resembles the Sprint Meter in blue instead of green. Staying underwater depletes it, using your spinning attack depletes it faster, and whatever you do, don't inhale the purple-colored bubbles (they're toxic). Running out of oxygen will quickly drain hearts until Link surfaces or drowns. There is a potion that slows the rate Link consumes oxygen, as well as a potion medal that prolongs the effects of potions (including the air potion); using the two at the same time makes the difficult Tadtone quest (which takes place underwater) much more manageable.
• Monkey Island:
  • While oxygen seems to be unlimited in the games, if Guybrush Threepwood stands around underwater for a really long time, he will die. This is really more of a gag death, as it's literally the only way to die in the games. This is, of course, in reference to Guybrush's special talent to hold his breath for ten minutes (a fact he'll repeat to anybody willing to listen). You literally have 10 minutes to solve this puzzle/get out of the water, which is intentionally much longer than most people will need.
  • In Tales of Monkey Island, Guybrush can intentionally go underwater, and if you spend a little less than ten minutes of gameplay underwater, Guybrush will remember his limit and go back to dry land. Thankfully, there's only really one or two areas where you need to be underwater, they're incredibly straightforward to navigate, and like it's been said before, ten minutes is a generous amount of time.
• The remake of Ninja Gaiden has one of this, but it ceases to be an issue once Ryu acquires an oxygen tank and draws on it from his Hyperspace Arsenal.
• Ecco the Dolphin. Of course, since the whole game was set underwater and dolphins can hold their breath for quite a while. When the oxygen meter runs out, health begins to drain.
• In addition to being a certified death incarnate, Rico Rodriguez in Just Cause 2 can swim underwater for a ridiculously long (for a video game, at least) amount of time. His oxygen is counted by a small circle that counts down from 99 by two every 2 seconds. This means that Rico can stay underwater for approximately one minute and 50 seconds, which is around what a fit human can accomplish in real life. Not quite Super Not-Drowning Skills, but quite impressive compared to other games.
• Tomb Raider uses a couple of variations on this:
  • While most of the games use a standard oxygen meter, Tomb Raider Chronicles used a special diving suit on one level that had confusing (since they never told you) additional mechanics: the suit had near infinite air, but as you bumped into walls and rocks, Lara audibly becomes stressed and begins breathing heavily, at which point you begin to lose oxygen quickly, meaning you had to avoid hitting things.
  • Tomb Raider III also has an underwater propulsion vehicle that makes you move faster, but it's less useful than just swimming as it decreases your general mobility and must be got off of to use switches and other items. Water in arctic levels also had a hypothermia bar that went down faster than the oxygen bar, but functioned much the same way.
  • In Tomb Raider: Legend and Tomb Raider: Anniversary, oddly, Lara is much slower underwater and has a much shorter air meter.
  • Tomb Raider: Underworld changes things up again, with Lara going back to being almost as fast as in the original games, and having such a long oxygen bar it borders on Super Not-Drowning Skills (that is in the rare instances where she swims without scuba gear, where it is that trope).
  • Decrease in health also functions differently depending on the game. Prior to Tomb Raider: Legend, health usually decreases at a fixed steady rate. During and after Legend, the decrease in health rate is usually a slash of a quarter of the health bar every two seconds, or an eighth, depending on the difficulty level setting.
• In An Untitled Story, in addition to a life meter indicated by a red heart you also have an air meter, indicated by a blue heart, that drops when you're in water and is restored by getting out of water, touching Oxygenated Underwater Bubbles or standing on jets of oxygen. Once it drops to 0 you start getting damage restrained only by Mercy Invincibility.
• Endless Ocean has an oxygen meter for your air tanks, but it's a rather long one and most tasks get completed without running out of air ever being a factor. When it does run out, you get warped back to the boat. The sequel does tweak things a bit; dangerous fish attacking you knock your air out faster. Certain equipment upgrades up your air supply in both games.
• Deep Fear counts down the amount of air left in any given room. Firing your weapon makes it go down slightly faster. When it reaches 0, you pull out a backup air supply that carries over from room to room (and is mandatory in some rooms which are flooded with water or filled with poisonous gas). When that runs out, you asphyxiate. This is intended to add a layer of tension to the game; however, various panels in the levels can refill the air supply in both the rooms and your backup air, seemingly infinitely, and special air grenades exist to fill any given room up with air as well, which are plentiful in supply.
• Dishonored has one of these for you. The NPCs, however, aren't so lucky, as they die the second a single polygon touches water. This is particularly frustrating in a Pacifist Run, as the game gives no indication of this, other than when Sokolov instantly dies if he is dropped in water (with the player having to drag his unconscious body back to Samuel, so this is basically Game Over).
• Shadow Man has a rather short one for Mike when he's in Liveside, and running out means instant death. As Shadowman, he becomes an immortal Zombi and has no need for air. Fittingly, underwater sections in Deadside tend to be much longer than they are in Liveside.
• A Hat in Time has an unorthodox Oxygen Meter that masquerades as a swim stamina meter. While Hat Kid can swim, she can't dive underwater unless she drops in from a long fall or if she uses the Ground Pound of her Ice Hat's statue form, with the only option from there being the jump button to swim upward. Whether she's underwater or treading the surface, 4 bubbles appear and drain after a few seconds, to which Hat Kid starts flailing around in a panic. This is a rare instance in a game where drowning can occur even after surfacing from a dive, as you have to touch land in order to restore the meter.
• Horizon Zero Dawn has an oxygen meter for when Aloy dives underwater whilst stealth-swimming; this makes it easier for her to sneak up on enemies in or near the water and harder for her to be detected. However, if she stays under for more than approximately 30 seconds, Aloy begins to drown and she flails whilst making pained groaning and choking noises — her health decreasing rapidly until she either re-surfaces or suffocates. Of course, she can use any health-granting items on her person to survive longer, but it does raise the question of how she's able to eat whilst holding her breath.
• The LEGO Movie Videogame has a swimming section in the mission "The Depths" that slowly drains the characters' health over time, which can be replenished by collecting blue hearts.

Fighting

• Super Smash Bros. Brawl has an invisible one just for swimming. Some characters (e.g. Squirtle) can swim longer than others (e.g. Charizard), but anyone will sink eventually. In the Subspace Emissary, some stickers can increase the length, but there really isn't any need for it. Super Smash Bros. Ultimate expands on this by having certain characters — namely Sonic, Inkling, Incineroar and Charizard — outright take damage from being in the water on top of the meter itself, and are constantly seen in their "drowning" animation when swimming.

First-Person Shooter

• In the Half-Life series, your hazardous environment suit provides you oxygen for a limited time. Oddly, the same meter that powers your sprint ability and flashlight is used for this in the second game. Once the suit runs out, Gordon has to start holding his breath. Once that runs out, your health starts dropping, but regenerates just as gradually when you come up for air.
• Far Cry:
  • In Far Cry, your Sprint Meter doubles as a Oxygen meter. It makes sense, because if you sprint for an extended period of time, what are you going to have to catch?
  • Far Cry 2 had your standard oxygen meter that, once empty, would begin to drain your life instead. However Far Cry 2 also allows you to heal for free with the press of a button. This wonderful Good Bad Bug led to what the fans call DEADLY AFRICANIZED WATER: you can swim for an eternity in it, provided to stop every so often to pull the barbed wire out of your flesh that the water inexplicably leaves there. Later games corrected this by merely having you drown when your breath ran out.
• In Hands of Necromancy, the moment you enter an underwater area, a 30-second timer appears onscreen and you need to either clear the stage or resurface before the timer hits zero. However you can collect a morphing spell turning you into a water serpent, which removes the timer and allows you to stay underwater for as long as you need.
• Bungie's Marathon series feature an especially heinous, literal Oxygen Meter: Your armored suit's HUD doesn't indicate how much oxygen remains in your lungs and blood, but in ITS compressed oxygen tanks! Since your suit lacks any way of refilling it with ambient oxygen, you must locate compressed oxygen dispenser panels or tanks of compressed oxygen to refill it. Worse yet, the player character apparently refuses to hold his breath, as if his suit's tank is empty he will instantly faint from even momentary immersion. It's rare to have trouble with Oxygen underwater (or sewage, or lava), but the back-to-back vacuum levels (three in a row, if you visit a secret level) in Marathon Infinity have a nasty reputation. The one vacuum level in Marathon was also infamous.
• Turok has a fairly unremarkable one, although you'd kind of expect a muscled-up warrior like him to be able to hold his breath a bit longer.
• Alpha Prime uses an Oxygen Meter on the asteroid's surface, refillable through the use of oxygen dispensers, or simply by walking back into an airlock.
• Will Rock has the traditional meter for the underwater sequences. If it runs out, you can always replenish your health with healing packs and bandages if they're at hand.
• A variation from Metro 2033: your wristwatch tells you how much time you have left on your gas mask before you need to switch filter canisters. Spend too long in areas with toxic atmosphere and you die. Since there's no HUD, you have to check your wristwatch constantly to see how much time you have before you have to change filters. And just because you're required to wear the gas mask doesn't mean it can't be damaged either, making any surface expedition a tense journey to avoid any serious conflict. You also need to remember to take off the mask as soon as it's safe to breathe, or it might get damaged the next time you get attacked.
• While you don't get a visible oxygen meter in Team Fortress 2, stay underwater too long and your character will begin to take damage and make choking noises as the screen tints blue round the edges with each "hit" taken, eventually dying in the same manner as an environmental hazard when their health runs out. Health lost from drowning is restored by coming up for air, but pauses if you go back underwater. Oddly enough, Medics and Dispensers can heal players faster than drowning can kill them, so they're sort of like oxygen masks or tubes.
• Doom³ has the oxygen meter only visible outdoors, and begins depleting when you're outside the inner areas of Mars City. You can even refill it by getting scattered air canisters.
• In Borderlands: The Pre-Sequel!, the player can go out onto the open-space surface of the moon where the game takes place. The player's oxygen tanks will slowly deplete, but can be instantly replenished by entering pressurized areas or by collecting oxygen canisters. The only character whose oxygen doesn't slowly deplete is Claptrap due to being a robot.
• Dark Forces features a gas mask that lets you get through toxic air safely, but drains battery to do so.
• Jedi Knight: Dark Forces II does not have a visible oxygen meter, but it doesn't mean you won't take damage from staying underwater for too long.
• Unreal lets you spend a few seconds swimming underwater before your character starts losing health due to lack of oxygen. You can extend that time with expendable SCUBA gear you can occasionally find. In Return to Na Pali, your "benefactors" give you a SCUBA gear that recharges every time you resurface.
• South Park: You can take a character underwater but there isn't any indication that there is a time limit, which may make you think the game gives Super Not-Drowning Skills, only for the character to start rapidly losing health after a while.
• Left 4 Dead and Left 4 Dead 2 doesn't have a visible air meter, but survivors who are submerged underwater for too long will start losing health until they get out of the water. Official maps that have very deep water can kill survivors that fall in it, but some custom maps can let survivors be fully submerged without dying instantly.
• One of the random mission modifiers in Deep Rock Galactic is low O2, which enforces an air meter on the players. Running out of air completely will damage a player's health until they get some air. Getting air comes from several sources, such as being near the M.U.L.E., supply drops, the Drop Pod, and other devices.

Miscellanous Games

• In the Wii Play: Motion minigame "Treasure Twirl", your diving suit-clad Mii has to dive into the sea to salvage the treasures that hide in it, but they have to get back up before they run out of oxygen. Thankfully, there are some conveniently-placed oxygen tanks underwater so you can slightly refill the oxygen meter during the dive.

MMORPG

• World of Warcraft has two of these. A traditional oxygen bar for underwater, and a fatigue bar to prevent you from swimming out too far. The first one can be bypassed by potions or spells. The second one on depleting completely begins draining your health, and can be circumvented by healing yourself to easily swim to the end of the map. The undead Forsaken can also stay underwater for much longer. This used to be significantly more useful until they extended the oxygen bar for all players, so that now everyone usually has plenty of time to fulfill their task. They can't seem to decide on how long the oxygen meter should be, before the Burning Crusade expansion, and shortly into Wrath of the Lich King, it was one minute long, halfway through wrath, they increased it to roughly five minutes, and as of Cataclysm, it's back down to roughly two minutes. As of Mists of Pandaria, the Forsaken no longer have a longer oxygen meter than the other races, while as of Warlords of Draenor they no longer have an oxygen meter in the first place.
• Dungeons & Dragons Online has a breath meter whenever a PC goes underwater. When the bar empties, the character starts taking damage. Unfortunately, surfacing does not heal any damage taken due to drowning.

Party Game

• In Sonic Shuffle, the first board, Emerald Coast has underwater sections. Sonic and his friends can only spend five turns underwater. If they don't land on an oxygen space or resurface within those five turns, they will drown, losing a turn as a result.

Platform Game

• In Banjo-Kazooie, the Oxygen Meter is represented by blue-colored honeycombs (in analogy to the yellow honeycombs that represent the standard health meter); it normally lasts about 60 seconds from a full meter, and if it runs out, you immediately drown. Rusty Bucket Bay has oily water that not only drains the meter twice as fast when submerged, but drains it at the regular speed when on the surface (this also happens with the water in Click Clock Wood in winter, due to its low temperature). This is rectified slightly in Banjo-Tooie, where once the Oxygen Meter goes, your health starts to go down really quickly instead (this is also the case for areas where oxygen is depleted due to toxic airs or very naughty smells); there's a sidequest in Spiral Mountain whose reward is an upgrade to the oxygen meter's length. In both games, certain transformations allow you to stay underwater indefinitely.
• Conker's Bad Fur Day and its remake Conker: Live & Reloaded has one of these once you're able to swim underwater (namely after consuming some pills in the Poo Cabin). When you're underwater, Conker's face and a stream of bubbles represents your air. As your air runs down, the stream of bubbles grows shorter, and Conker's expression becomes increasingly desperate and his face starts turning blue. When his head droops, your chocolate bar (i.e., your health) starts falling apart rapidly. All six pieces go in about five seconds, so unless you're near the surface, you run out of air, you're probably gonna die. The meter lasts about 25 seconds in the original, and about 70 seconds in Live and Reloaded. The other main difference between the two is that you begin losing health immediately when the last bubble goes in the original, while in the remake, your last bubble goes at about 15 seconds remaining, and that's when Conker's expression really starts getting desperate, shaking and ultimately having his eyeballs begin to roll back as his head droops and his eyes close.
• Donkey Kong Country: Tropical Freeze has a meter that applies to all Kongs, both when played as together or separately. Touching air bubbles or items surrounded by air will replenish the meter.
• Doujin Soft developer Fox Eye has this mechanic in every last one of their games. This is mainly out of its lead designer's huge fascination with underwater fantasies and drowning perils, making this trope the developer's modus operandi. Even in games where the Oxygen Meter isn't present (and several games where it is), the developer puts great care and graphic detail in showing that it still plays a significant role through the character's distressful body language as they're running out of air.
  • Holdover gives Marie a meter that can be upgraded by collecting blue hearts around the facility. You'll need it, too. She spends a lot of time underwater, and the anklets that are repairing her organs also prevent her from swimming.
  • Aqua Cube makes you handle two. One for the sibling you're playing as, and one for the trapped sibling you're rescuing. The controlled sibling has a bubble that shrinks while they're underwater, while the trapped sibling has an animated portrait that gets more and more dire the closer they are to drowning. An Underwater Kiss is all you can do to keep the trapped sibling's oxygen full besides dropping the water level, but it comes at the cost of your own and this becomes impossible to do if the trapped sibling is locked in a cage.
  • BLUE GUARDIAN: Margaret has one that gets affected by the titular character's "Excitement Meter". The higher it is, the faster her oxygen drops underwater. The player can manually lower the Excitement Meter before or after taking a dive to prevent Margaret from drowning too early.
  • Hades Vanquish has one that is capped by Mana's Life Meter. So how long she can hold her breath underwater depends on how much damage she took beforehand. If Mana has no items to recover her health or revive her after death, Failure Is the Only Option if you're forced to take a dive to get further through a floor with little health left, which means seeing her drown in only a few seconds.
• Distorted Travesty 3 has a blue bar on the left side of the screen that appears whenever your head is below the water. Additionally when it's within five seconds of running out, big green numbers straight from Sonic the Hedgehog appear right above the player's head and start counting down.
• Gex 3: Deep Cover Gecko: Gex is given a red bar slowly emptying whenever he dives into water. Earlier games gave him Super Not-Drowning Skills where Gex swims Mario-style, pressing the jump button to float upwards and not needing any oxygen.
• Super Mario Bros.:
  • Most 3D games have one (With the exceptions being 3D Land and 3D World which allow the player to swim indefinitely since they play closer to the 2D games). The original Super Mario 64 makes the odd decision of using the Life Meter in lieu of a separate oxygen meter, while still allowing you to catch your breath when surfacing, which basically means that you can refill your health for free by swimming around at the surface of any deep body of water, or continue holding your breath as long as you gather coins (which heal your life meter).
  • Super Mario Sunshine and both Galaxy games use a separate oxygen meter (though coins still refill it when underwater, and in Sunshine, it basically replaces your health meter while you're underwater). Super Mario Odyssey also uses a separate meter, however, the need for oxygen can be bypassed altogether if Mario uses Cappy to capture an aquatic creature that breathes water, such as a Cheep Cheep. The oxygen meter is also turned off altogether in Assist Mode, allowing Mario to stay underwater indefinitely.
  • Mario Party 6: The minigame Sink Or Swim has three characters swim in the waters of a flowery lake while the fourth player is standing on the surface to drop mines onto them to try to eliminate them. Each of the swimming players has a heart-shaped gauge that will deplete the longer they spend underwater; rather than drowning, they'll automatically rise to the surface to breathe anew once their oxygen depletes completely, making them easier targets for the solo player. The solo player wins if they manage to hit all the other three with the mines; however, if at least one swimming player survives during 30 seconds, then the trio wins.
• The Ty the Tasmanian Tiger games use the Mario 64 variant, sharing the properties of being an oxygen meter and an energy meter, with exactly the same consequences.
• Ratchet & Clank (2002): Ratchet then gains an oxygen mask about halfway through the first game — and unlike most of his weapons and items, the mask makes it to every subsequent game, making it a non-issue for the rest of the series.
• Sonic the Hedgehog:
  • Two-dimensional games give the Player Character an invisible oxygen meter lasting 30 seconds. Three warning chimes are played at five-second intervals; after a total of 18 seconds, a countdown begins, running from 5 to 0 (each of these lasts about two seconds) followed by automatic death when it runs out. The indication of how much time remains is based on a infamously-chilling background music that gradually speeds up as the timer reaches zero.
  • This is the same case for the first Sonic Adventure game, but in its sequel, two-thirds of the cast dies upon falling into water (save the small patch in the Chao Gardens, though Tails is short enough that he can drown in one area, the same as in the first game). This eventually became the case for everyone over the course of the 3D series while the 2D games retained the classic countdown. Such is the case of the underwater Knuckles level "Aquatic Mine", which can be quite dangerous until you find the infinite oxygen item.
  • Averted in some levels, where Sonic displays Super Drowning Skills, dying if he so much as touches the rippling water at the very bottom of the game world (if you're lucky, he may only lose rings, and bounce back onto land). On others, water is a relatively benign substance, merely reducing your running speed and jump height (swimming is out of the question), and in some cases (where it takes up a significant portion or even all of the level) requiring you to find air to breathe. Worse, there are even some places where the two are mixed; go too deep on, say, the Jungle zone in the 8-bit version of Sonic the Hedgehog 1 or the Aquatic boss fight, and you'll instantly pop your clogs.
• Cave Story has a meter which appears when the protagonist is underwater. Since the protagonist is an armed scout robot, when submerged in water his internal compartments get slowly flooded with water until he can't operate anymore. Curly Brace, also a robot, carries an air tank which lets her survive underwater indefinitely, which she gives to the protagonist at one point.
• The NewZealand Story did this, with the added implication that it may have actually been water in Tiki's lungs — swimming up to the surface would naturally allow your oxygen level to (slowly) replenish itself, but the process could be accelerated by spitting water. Pretty deadly water it was, too, as it could kill most enemies.
• Radical Rex plays this entirely straight. Not only do you get a bar, but you have to either surface to refill it, or (ugh) lock lips with a big fat fish that is somehow able to maintain neutral buoyancy despite apparently being full of air. Oh, and if you touch the un-inflated fish (which this type will become upon giving up its payload), you'll lose a big chunk of air. There are also "bubble" powerups good for about half a deep breath. And if you get caught in the anemone's tentacles, the meter drains almost immediately to zero (though whether it's this or some kind of poison in them that kills you is debatable).
• Jungle King / Jungle Hunt uses this during the swimming levels.
• All three Disney's Magical Quest games have them, but the meter is only visible in the third.
• In Jables's Adventure, your oxygen counts down from 100. It happens so quickly that you really can't accomplish anything underwater prior to receiving the SCUBA gear (which allows you to stay underwater indefinitely).
• Kirby Mass Attack is the only game in the Kirby series which has this meter.^note And one of the only games to not feature Kirby in scuba gear when underwater. This meter is shared by all the Kirbys and the more Kirbys the player has, the bigger the meter is.
• The first Rayman game has Super Drowning Skills, the second has an Oxygen Meter which can be refilled by collecting blue lums (or by entering bubble vents in Rayman 2, and inhaling the large air bubbles Carmen the Whale provides for you in Whale Bay), and the third game onward lets you breathe underwater indefinitely.
• Space Panic may have been the first game to have an oxygen meter, though it was really no more than a level timer labeled "oxygen."
• Magical Doropie gave Doropie an oxygen meter in the underwater base levels. When it got low, it would beep until refilled by jumping into a convenient air pocket.
• Endeavor has an oxygen bar, which replaces the endurance meter when you're underwater. Getting the Flippers item in game slows down how fast your oxygen depletes.
• Ori and the Blind Forest has an oxygen bar that lasts for roughly 15 seconds before Ori's health begins to drain rapidly. Strangely, drowning in this game is the only way to die that doesn't employ Critical Existence Failure (Ori clutches at their throat and visibly inhales a lungful of water upon death, rather than exploding into a shower of magic sparks as usual), and can be averted entirely via an upgrade that ditches the meter for Super Not-Drowning Skills. The meter returns in Ori and the Will of the Wisps, but with one frustating change: instead of their health rapidly draining upon their air running out, Ori now drowns immediately.
• If a Sackperson in LittleBigPlanet stays underwater for 30 seconds without resurfacing or reaching a Bubble Machine, they pop from lack of air.

Puzzle

• Non-underwater example: the Mr. Driller series has an Oxygen meter that slowly depletes as you play, with the oxygen loss accelerating once you make it deeper underground. To stay alive, you need to pick up air capsules scattered throughout the mine.
• One type of puzzle in The Time Warp of Dr. Brain had you controlling a lungfish in an underwater maze. The lungfish would gradually change colors from bright green to purple as your oxygen ran out. Eating bubbles or finding an air pocket replenished it.
• The Hidden Object Game Hidden Expedition: Titanic was structured as a series of dives to the wreck of (you guessed it) the Titanic. The timer for each level was a SCUBA tank, that vented a little extra air with each mis-click. Some of the levels also had a second tank hidden in one scene, and finding it gave you some extra oxygen/time.
• Played with in the indie browser game "Asphyx" where you explore a partially-drowned mine. YOU are the oxygen meter. Yes, YOU are supposed to hold your breath when you are underwater.
• One level in Karoshi 2.0 takes place underwater and is finished by letting your oxygen meter drop to 0, a task made harder by Oxygenated Underwater Bubbles rising in droves.

Real-Time Strategy

• An example without water: LEGO Rock Raiders had a meter measuring the remaining oxygen in the various caverns. Some levels had infinite oxygen, but in others, it would be gradually consumed by your Rock Raiders. In those levels, building at least one Support Station is critical^note also the victory condition in one level, as it provides enough oxygen for up to nine miners to work worry-free.

RPG

• The Elder Scrolls:
  • Morrowind and Oblivion both have "Breath" meters which appear when the Player Character is completely underwater. The breath meter decreases over time, and once it empties, the player's health begins to drain rapidly. Skyrim keeps the meter, but makes it invisible — so the only indication that you've been underwater too long is when your health starts draining. All three games offer Water Breathing as a spell effect, and it also comes in the form of enchantments and potions. While under the Water Breathing effect, your breath meter will not decrease. Argonians, who canonically possess gills, have Water Breathing as a racial ability. In series' lore, they will use this as an Exploited Immunity. Renowned for their prowess in guerilla warfare, Argonians are known to ambush enemies from underwater and will often drag them into the water in order to drown them.
  • Morrowind has a Tribunal Temple quest which requires you to drown yourself as part of a pilgrimage. Once your health dips below 10, the quest will complete and your health will be restored. As your character only takes a fixed amount of (minor) damage for each second that they are underwater without air, it can take a high-level character at full health a ridiculous amount of time to finally "drown".
• Fallout: Fallout 3, Fallout: New Vegas, and Fallout 4, which use the same (or similar) engines to their aforementioned Bethesda Elder Scrolls sister series above, inherit this mechanic as well. It drains worryingly quickly, followed by massive health loss. Although a character in New Vegas can gain Super Not-Drowning Skills with the unique rebreather, again based on the very same effect as Water Breathing in The Elder Scrolls. An interesting variation on this is that the meter is more and more forgiving as you increase your Endurance attribute. Amusingly, some creatures in New Vegas will follow you underwater, despite having their own oxygen meter.
• In Deus Ex, your health would start decreasing when you run out of oxygen and start gulping water. While there are skills, items, and Upgrade Artifacts to increase the amount of time you can hold your breath, the powerful health regeneration Upgrade Artifacts and instant-use medkits allow one to use Hit Points as an extra Oxygen Meter.
• Swimming underwater in Gothic adds an oxygen meter in addition to the player's health and mana meters. When the Nameless Hero runs out of oxygen, the health starts draining instead, until he runs out of health and drowns. Notable because surfacing will make the meter invisible again, but will not instantly refill it — the player must stay on the surface for at least a few seconds, or will find on diving again that the meter isn't completely full.
• Mega Man Battle Network:
  • Mega Man Battle Network 4 Blue Moon uses one during AquaMan's chapter, when the net is flooded by his crying over (what he thought was) Shuko and her brothers talking about getting rid of him. This may be refilled by slipping into a homepage from the net.
  • In Mega Man Battle Network 5: Team Colonel and Team ProtoMan, there is a water dungeon which you have to guide your current Navi through. While they are underwater, they are perfectly fine until they run out of "cyber-air" (really?), at which point their HP starts dropping rapidly until you either hit a cyber-air pocket or exit the water. Oh, and there's random encounters the whole way, including while you're attempting to fight the currents that push you back and drain your air, and while you're trying to avoid the whirlpools that drain your air. There's also three areas of this, each one progressively more frustrating. This is one instance Capcom cut something out of the English release for a good reason — in the Japanese version, there were four areas. By the DS version, it was back up to four.
• When traveling on the ocean floor to Tane-Tane Island in Mother 3, the way you refuel your characters' collective oxygen bar is unusual. The amount of time you're able to survive without the aide of these machines is fairly realistic compared to most examples, though — around 30 seconds to a minute (with battles excluded). You get them kissed by big-lipped mermen. And if you run out of oxygen, you don't die — instead you get washed up on the beach at the beginning and have to start the underwater "dungeon" all over again.
• Final Fantasy:
  • There's an optional underwater dungeon in Final Fantasy V that gives you a timer. The boss is a Puzzle Boss, just to make things more "fun". It's Gogo the Mimic. How do you win? Do nothing. He's testing to see if you can be a good mimic — so mimic him mimicking you doing nothing. The faster you catch on, the more time you have to get out.
  • In Final Fantasy VII, the party has twenty minutes to defeat Emerald WEAPON, unless a party member is carrying the "Underwater" Materia, which replaces the timer with Super Not-Drowning Skills.
• Super Paper Mario uses a meter like this, but not for oxygen — the one place where Mario needs oxygen, he can somehow get all he ever needs from a goldfish bowl. No, the meter comes into play when shifting into 3D, where it depletes steadily and does damage if it runs out.
• Monster Hunter 3 (Tri) and 3 Ultimate use an oxygen meter during underwater combat, though the amount of time the player character can hold their breath for is a bit unrealistic, just not enough so that you're not forced to return to the surface, find oxygen bubbles underwater, or use a miniature oxygen supply bauble. One of the major fights in the game takes place exclusively underwater, so this becomes very important. Eating certain food combinations or using an Air Philter or Mega Air Philter will extend your already-generous oxygen meter, and raising the Oxygen skill to 10 points grants you the Endless Oxygen skill.
• Soma Union: In the Ripple Railway, there are some sections of the subway that are submerged in water. When traveling through these maps, the party has a limited amount of time they can hold their breath. Running into bubbles from pipes will refill the oxygen gauge and allow them to make it to the other side of these maps.
• Ys VIII: Lacrimosa of Dana: While none of the party members can swim and they sink like rocks, they can still go underwater, albeit with an Oxygen Meter that rapidly depletes and forces a respawn above water with some HP damage when empty.

Sandbox

• Minecraft gives you small air bubbles underwater. Once used up, you lose health over time. Helmets enchanted with the Respiration ability decreases oxygen consumption, including drowning damage.
• In Minicraft, a Retraux take on Minecraft, swimming through water rapidly depletes your stamina bar and, once it runs out, your Hit Points.
• Terraria:
  • Clearly visible in the game and health begins to drain after you run out of air. It is possible to keep yourself alive with health items and having a large health meter for lengthy periods of time.
  • Diving gear and breathing reeds greatly retards the rate of oxygen depletion, while the charms that grant you transformation into merfolk eliminate the bar entirely.
  • The Gills Potion allows you to breathe underwater. The Obsidian Skin potion also allows you to breath underlava (along with its lava immunity effect) as of 1.2.
  • Wearing the Lava Charm or the Lava Waders gives you a different type of "oxygen" that allows you to be submerged in lava for up to 7 seconds before you start to take damage from it. Both of those accessories can be worn together to extend that time to 14 seconds.
• Starbound gives you an air meter that appears and depletes when you're submerged in liquid (water/tar/poison/lava) or if you're in space, damaging the player rapidly once it fully empties. Equipping the Survival System removes this oxygen meter. Strangely enough, even the Hylotl still have this oxygen meter when underwater.
• Subnautica: The whole game takes place in a planet surrounded by water, so naturally it's present and you'll be keeping an eye on it a lot. At first you can only hold your breath for about 30 seconds, but you can craft oxygen tanks to increase that amount. Your PDA will give you warnings when you'll run out of oxygen, and once it runs out your vision will start fading until it goes black and you die. There are a few oxygen-producing plants underwater, which can restore some oxygen levels. The oxygen mechanic has some additional caveats like submerged depth affecting oxygen usage (unless you have Rebreathers equipped) and unpowered interiors not providing oxygen.
• Planet Explorers allows players to swim underwater for a limited time before they start drowning. Equippable scuba gear allows players to stay submerged for longer.
• Breathedge, being heavily inspired by Subnautica but set in space, also features an oxygen meter as a core mechanic. Your spacesuit starts with a pathetically small capacity, which is upgraded over the course of the game. Unlike Subnautica, you can't just swim to the surface when your tank gets low, so you have to keep a close eye on your distance from the nearest air supply especially in the early game.

Simulation

• Steel Battalion: Line of Contact adds one in the form of your view whitening up when the cockpit hatch is closed and your VT is shut down (either manually by toggle switches, the Rapier's Stun Rod, or the Earthshaker's Gauss emitter). Go without oxygen for too long and the pilot asphyxiates, taking you out of the match even if you have enough sortie points for another VT and deleting your pilot data.
• The X-Universe gives you a two-hour air supply on your spacesuit, though checking it requires you to open up the spacesuit's info screen. Two hours is usually plenty of time for you to do whatever you need to, although it's possible to run out if you're trying to patch up a capital ship's hull with the suit's repair laser. Somewhat bizarrely, when your oxygen runs out, you explode.
• Fisher-Diver has an oxygen meter that not only goes down when you dive underwater, but also whenever you use weaponry on the fish that swim in the ocean's depths.
• Elite Dangerous's starships have nigh-100% efficient closed circuit life support systems, but all that goes out the window if your cockpit canopy is shattered in combat. The oxygen vents out as your space suit automatically seals, and a ominous timer appears in the HUD indicating reserve oxygen levels. If you fail you enter a pressurized space station before the timer runs out, kaboom. The backup life support can be upgraded from the base 5 minutes up to 20 minutes.
• In FTL: Faster Than Light, rooms on spaceship can have pressure from 0 to 1 atmosphere (shown as white at 100% pressure and getting redder as it drops) which can be replenished by a working life support system and depleted by opened airlocks, fires, hull breaches, hacked life support or the Lanius. If pressure falls below 5% (indicated by red diagonal stripes), organic non-Lanius beings staying there start rapidly losing health and any fire there will get extinguished. Humorously, an upgraded medbay can restore health faster than underpressure depletes it.

Stealth-Based Game

• In the undersea levels of Assassin's Creed IV: Black Flag, Edward will slowly run out of air, shown on a meter. He can replenish his air by sticking his head in various pockets of air contained in overturned barrels or underwater caverns, or by simply returning to the diving bell used to reach the sea floor.
• All the Metal Gear Solid games feature an oxygen meter, which determines how long you can MANAGE TO AVOID DROWNING underwater, survive poisonous gas, or resist being strangled.
  • The first game, even though there is no reason to backtrack all the way to the heliport after acquiring the gas mask, took the time to distinguish between water and gas just in case the player decided to take the gas mask all the way back to that briefly flooded air vent to see what happens if you wear it.
  • Both Vamp and Liquid Ocelot, as bosses, also feature oxygen meters. The former has to resurface from the waste water when his meter empties (which you can speed up by shooting him or literally knocking the wind out of him by tossing in a grenade), while Ocelot's is purely cosmetic and only pops up when you're strangling him.
• The Thief games have an oxygen meter that looks like a line of bubbles across the bottom of the screen. If you knock someone unconscious and dump him in water, he will die in about the same span of time you would (so don't dump unconscious guards in swimming pools if you're running a no-kill mission). Averted however in Thief: Deadly Shadows, where Garrett has learnt Super Drowning Skills.

Third-Person Shooter

• Duke Nukem Time To Kill deviated from the first-person variant by actually providing the player with a LCD heads-up oxygen meter. There was the added caveat, however, of no scuba gear to be found.
• In Dead Space, this becomes visible once you enter a vacuum. As it depletes, Isaac begins to choke and gasp, which is just wonderful for your concentration. Thankfully, your time limit can be extended with upgrades to your RIG and restored with air canisters.
• Mass Effect features a variant; many levels have environmental hazards in the form of extreme heat, cold or gravitational pressure. The player is safe inside their vehicle, the Mako, but if they leave the vehicle, a meter will appear and slowly deplete. If it empties, the player receives constant damage, but the meter instantly fills back up if the player enters the Mako or a pressurized environment such as a building. Equipping certain types of armor that were noted as having been designed for use in hostile environments would slow or possibly even stop the meter from draining.
• In level 3 of MDK2, Dr. Hawkins is trapped in a large room with an open airlock that's sucking him towards it. The player has 10 seconds, shown on the screen, to find a way to stop getting sucked into space and then find a spacesuit (or in this case a fishbowl) so he can breath.
• Resident Evil 6: Leon is given one when he traversing through a flooded cavern with zombies while having to find safe spots to get some air.
• The aim of Survival missions in Warframe is not just to Hold the Line against fiercer and fiercer enemies, but also to look after your draining life support meter, which can be replenished by tiny capsules dropped by enemies and larger capsules dropped by your Mission Control. When life support drops to 0, your life will start draining and you will have no choice but to extract; unless extraction is not available yet, in which case you fail the mission.

Non-Video Game Examples

• In the pinball table Scooby-Doo, Where Are You! (2023), the first stretch of Captain Cutler's mode requires the player to fill up an oxygen tank before going underwater to search for clues. The oxygen meter then serves as a time limit that can be refilled by hitting a specific set of targets.

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