Subnautica 2 Oxygen Guide - How to Replenish, Increase Maximum Oxygen

This Subnautica 2 Oxygen Guide shows how to refill oxygen and increase your maximum oxygen capacity so that you can stay in the water for longer. While exploring the ocean in Subnautica 2, you may notice that your oxygen levels start running low. This makes it very difficult for you to survive. In Creative Mode, this is not really a problem because you are immortal, but Survival Mode makes every dive more dangerous. Your oxygen drains quickly underwater.

Oxygen Guide – Subnautica 2

At the beginning of the game, you start with 45 oxygen. While underwater, this slowly decreases by 1 point every second, which means long dives are difficult early on. Because of this, you constantly need to look for ways to refill your air supply.

Move to the Surface

The easiest way to recover oxygen is by swimming back to the surface. However, this becomes harder once you start exploring areas far below.

Any powered base with proper rooms/corridors and a hatch will refill your oxygen as long as you are inside. You can also enter abandoned Colonist Bunkers scattered around the world, which act as safe spots. Later in the game, entering the Tadpole vehicle also restores your oxygen.

Using Oxygen Tunics and Air Sources

While swimming and exploring through underwater areas, you may notice strange blue stems called Oxygen Tunics. These plants release bright blue air bubbles that instantly restore some oxygen when you swim through them.

You might also come across abandoned air tanks left behind by other divers. These provide extra oxygen as well, giving you another source of oxygen.

Crafting the Air Bladder

One of the survival tools you can craft is the Air Bladder. This item is made through the Fabricator using 2 Titanium and 1 Rubber materials. Once equipped, you can use it anytime underwater to instantly restore 45 oxygen.

After using it, you need to refill it by returning to the surface or entering a safe oxygen area like a base or vehicle.

Portable Oxygen Generator

As you progress further in the game, you can unlock a stronger oxygen device known as the Portable Oxygen Generator. The blueprint for this device is found near the Great Jaw, which is also known for its Lithium resources. While scanning objects at Great Jaw, you need to avoid the creature’s pink tendons because if you get trapped, it will quickly kill your character.

After unlocking the blueprint, the device can be built using 3 Titanium and 2 Lithium through the Habitat Builder. The generator works with a Basic Battery. You should have a Basic Battery in your inventory while underwater. If the generator stored enough oxygen, using it gives 15 oxygen. If only a small amount has regenerated, it restores 5 oxygen instead.

Increasing Your Maximum Oxygen Capacity

Besides restoring oxygen, you can also permanently increase the total amount by crafting better Air Tanks. You again need to craft them at the Fabricator.

The Standard Air Tank only requires 2 Titanium, 2 Silver, and a Rubber to craft. Once equipped, it increases your oxygen capacity to 75.

A stronger upgrade called the High Capacity Air Tank can be unlocked later in the game. To find its blueprint, you must travel far away from the Lifepod toward the Research Center/Alien Ruins area. A datapad near the entrance unlocks the recipe.

Crafting this advanced tank requires a Standard Air Tank along with a Plasteel Ingot, which is created through the Processor using 2 Titanium and a Lithium. After equipping the High Capacity Air Tank, your maximum oxygen increases even more to 120.

That is all for this guide. Additional Subnautica 2 guides are linked below:

This concludes our Subnautica 2 Oxygen Guide. If you want to add anything to this guide, feel free to use the comments section below.