Subnautica 2 Portable Oxygen Generator and Air Tanks

01

How oxygen works in Subnautica 2

You start with 45 units of oxygen, shown at the bottom left of the HUD. Shallower than 100 m you use one unit per second, between 100 m and 200 m three per second, and deeper than 200 m five per second, unless you wear a Rebreather. Those rates come from the wiki's Oxygen page and were repeated on its Rebreather page in August 2026, but its Depth page lists 2 per second at 100 to 199 m and 3 per second below 200 m, so treat the deep-water numbers as unconfirmed.

The PDA warns you at 10 units left, and at 30 when you are diving far from the surface. Once you run dry the screen fades, leaving roughly four seconds to reach air before it goes black and about four more before you die.

Your oxygen refills when you surface, enter a powered seabase or vehicle, or return to the Lifepod, which always has air. Tanks keep their fill level when moved to your inventory, and swapping an empty equipped tank for a full one restores your reserve, so a second tank filled beforehand works as backup air. If you are still on your first dives, start with the beginners guide.

02

Subnautica 2 oxygen tanks compared

Subnautica 2 oxygen tanks are called air tanks in game and go in the Air Tank slot, one of only three equipment slots in use alongside head and feet. The game files contain three tiers, but only two can be crafted in Survival.

Capacities are in oxygen units, which only equal seconds while you stay above 100 m. Below 200 m without a Rebreather, a full 120 units lasts about 24 seconds at five units per second (40 at the Depth page's three), which is why the Rebreather matters as much as the tank. For the ingredients, see the crafting materials guide.

03

How to get the High Capacity Air Tank in Subnautica 2

The Subnautica 2 High Capacity Air Tank is crafted from a Standard Air Tank plus one Plasteel Ingot at the Fabricator, adding 75 units to your base supply instead of 30. Its blueprint comes from a Recipe Data Card. The wiki's item page names Spires Wreck 1 and the Stairway to Heaven wreck in its text, while its location table lists four cards at three sites.

Plasteel Ingots come from the Processor (2 Titanium and 1 Lithium, two minutes per ingot), so you need that blueprint too. One scan unlocks it, and Spires Wreck 1 also holds a Processor fragment at -352031, 458217 @ 90m. Lithium deposits sit inside the Great Jaw and in the Graveyard Caves and need a Sonic Resonator; the lithium guide has the details.

Spires Wreck 1, in the shallow Dolerite Spires, holds the shallowest card. The Stairway to Heaven wreck lies near 325 m behind Bloom Biofilm that you clear with a Sonic or Feedback Resonator. Its two cards are in the sleeping quarters reached through the ventilation shaft and on a balcony on the lower level, and the cave beneath the wreck holds at least seven Oxygen Tunics.

The Ultra High Capacity tank is not available

The Subnautica 2 Ultra High Capacity tank is real, but only in the game files. The wiki marks it as datamined and says its blueprint is unavailable; it was usable in Creative mode at the start of Early Access and was removed in the 1.1 update. For now, 120 units is the ceiling.

04

Portable Oxygen Generator: fragments, recipe and use

Both fragments sit inside the Great Jaw, the giant clam in the Dolerite Spires.

The Great Jaw is an aggressive ambush predator that slams its shell shut when the sensory structures at its core are disturbed. The wiki's suggested safe way in is the hole on its west side, squeezing between the fleshy tendrils.

Once unlocked, the generator is a Utility item in the Habitat Builder that you carry like a Portable Locker. Set it down in open water or mount it on any hardpoint, insert a battery, wait, then interact with it to inhale. A gauge on its side shows how much oxygen is stored.

The wiki is blunt that it is somewhat impractical: a fully charged Basic Battery runs flat after only a few uses, and the Air Bladder or a Tadpole is usually the more flexible air supply. It makes most sense at a spot you will work for a while where a Tadpole cannot follow, with spare charged batteries in your pack. The wiki does not document how much oxygen it can hold or exactly how fast it drains a battery.

05

Rebreather and Air Bladder

The Rebreather goes in the head slot and keeps consumption at one unit per second at any depth. It costs 2 Fiber Mesh and 1 System Chip at the Fabricator, and scanning one Rebreather unlocks it. The wiki's spots include a wreck on the south edge of the Necrolei Hills (-352596, 408993 @ 25m), wreckage east of the Great Jaw (-324026, 462902 @ 45m), a Colonist Bunker in the Dolerite Spires (-352853, 450545 @ 88m), the Lander Garage wreck, which needs a Repair Tool (-308114, 411795 @ 50m), and a crate in the Empty Hold wreck (-288642, 435198 @ 80m).

The Air Bladder (2 Titanium and 1 Rubber, known from the start) is your emergency tool. It stores 25 units of air and can either lift you up to 116 m toward the surface or be inhaled, but inhaling empties it and disables the lift until you refill it at the surface or in a powered habitat. Bubbles from an Oxygen Tunic also refill every Air Bladder you carry.

06

Oxygen biomods

Oxygen Control is the only oxygen biomod in the game right now. It is passive, listed as unlocked by default, and slows consumption while you hold still; the wiki gives a 75% reduction but also describes it as one unit every three seconds, so the exact figure is uncertain. Biomods are equipped at a Biolab, and you start with one passive slot. Since the Adaptive Measures update, bioscanning creatures unlocks more passive slots, at 10, 20, 40 and 80 scans according to the wiki.

Two related biomods exist only in the game files: Oxygen Therapy (slowly regain health at full oxygen) and Dive Bladder (sink faster when descending feet first). The wiki lists both as unimplemented. Biomods are optional, unlike adaptations, which you need for progression; see the adaptations guide.

07

Base and Tadpole oxygen

Seabases produce oxygen only while they have power. If the power runs out, production stops and you lose air even indoors, and the Habitat Builder's own quick-start steps have you build a solar panel to power the habitat's oxygen generator.

A powered Tadpole works the same way. Its databank promises unlimited oxygen while powered, and an oxygen port under each side handlebar refills riders holding on outside. The Haul chassis adds a port at every seat, and its upper handle port works if you just swim close. Buddy System Hotfix 1 (September 1, 2026) made those refills reliable for players attached to a Tadpole or Haul, while the Buddy System update fixed a bug that let riders of an unpowered Tadpole or its Haul keep their air. The Tadpole guide covers power cells and charging.

08

Wreck puzzles and quick oxygen tips

• Wrecks: the Adaptive Measures update (Early Access 1.1, July 8, 2026) added more traversal and oxygen puzzles to wrecks and moved or added rewards, so check your air before you push deep into one.
• Leaks and tunics: the wiki's Oxygen page says damaged, leaking air tanks in some pioneer seabases refill you, and Oxygen Tunics, anchored creatures found in many biomes including the Dolerite Spires, give 30 oxygen per bubble.
• Depth: below 200 m the Rebreather cuts your use from five units per second (three by the Depth page) to one, so craft it before you chase deep blueprints.
• Hold still: with Oxygen Control equipped, waiting motionless costs far less air than swimming.
• Co-op: since the Buddy System update, a revived player keeps their equipment and gets a small amount of oxygen back.