How to increase your max Oxygen in Subnautica 2 (original) (raw)

Everything you need to boost your Oxygen meter to 120!

A group of players in Subnautica 2 swim through the ocean, interacting with one another.

Image credit: RPS/Unknown Worlds

One of the most powerful and important upgrades you can make to your equipment in Subnautica 2 is to increase your max Oxygen supply. When you begin the game, you are limited to a maximum of 45 seconds of breathable air before you start to drown. There are ways to top up your air supply during a dive (including Oxygen-emitting plants, and sacrificing the air in your Air Bladder for an extra Oxygen boost). But in reality, your progress will be severely limited until you craft yourself an Air Tank to boost your Oxygen supply.

In this guide, I'll walk you through everything you need to get in order to craft the three most important Oxygen supply items: the Standard Air Tank, the High Capacity Air Tank, and the Rebreather. Each of these serves as a massive progression milestone, and it's worth completing all the steps below as quickly as possible in your playthrough.

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How to increase your max Oxygen supply

You can upgrade your Oxygen supply by crafting a Standard Air Tank in the Fabricator of your Lifepod, your starting spawn point in Subnautica 2. Once you've crafted a Standard Air Tank and equipped it in your inventory, your max Oxygen supply will be increased to 75 seconds.

Later on, you can upgrade your Oxygen supply a second time by crafting a High Capacity Air Tank, which increases your max Oxygen to 120 seconds. This will allow you to dive far deeper and for far longer than you'd ever be able to on just the default 45 seconds of breathable air.

Here's the full breakdown of the Air Tank upgrades in Subnautica 2, and how they affect your maximum Oxygen supply:

Upgrade Max Oxygen Recipe
No Upgrade 45 seconds None
Standard Air Tank 75 seconds 2x Titanium, 1x Rubber, 2x Silver
High Capacity Air Tank 120 seconds 1x Standard Air Tank, 1x Plasteel Ingot

In addition to the two Air Tanks, you can also craft a Rebreather once you've unlocked the recipe. The Rebreather doesn't increase your maximum Oxygen supply, but it negates the increase in Oxygen consumption as you dive ever-deeper. Once you pass 100 metres depth, your Oxygen will tick down twice as fast, with further depth thresholds prompting even greater Oxygen penalties. With the Rebreather equipped, none of these penalties apply. You can breathe as easily at 300 metres as you can at 3 metres.

Now let's walk through everything you need to collect in order to craft these three all-important Oxygen-related pieces of equipment.

How to craft a Standard Air Tank (Requires Silver)

A close-up of the Fabricator menu in Subnautica 2, where the player has selected a Standard Air Tank to be built.

Image credit: RPS/Unknown Worlds

You can craft a Standard Air Tank using the Fabricator in your Lifepod (or any Fabricator in your base). Here are the materials you need:

Titanium is extremely commonplace, particularly in the starting biome, so this will be no issue. Rubber can be crafted from 2x Lucifer Rotsacs in your Fabricator; these are the glowing orange orbs in the centre of certain flowers dotted around the seabed of the starting biome.

The tricky part to this recipe is getting the Silver you need, because Silver is hard to find unless you know where to look. We have a full guide on where to find Silver in Subnautica 2, but briefly: head to the cave around 200 metres north of the Lifepod, just beyond the giant Angel Comb. You'll find plenty of mineable Silver here.

The player in Subnautica 2 approaches the giant Angel Comb plant at the location the "Blackbox (Anita)" signal.

The player in Subnautica swims down towards a Silver cave entrance in the ocean floor beside a platform of wreckage, near the Angel Comb.

Image credit: RPS/Unknown Worlds

The player in Subnautica 2 mines a Silver node from the wall of a cave marked by glowing teal and pink flowers.

Image credit: RPS/Unknown Worlds

Once you have all the required materials, head back home and craft the Standard Air Tank in the Personal/Equipment section of your Fabricator. Once crafted, it will immediately be placed in the suitable equipment slot on the right-hand side of your inventory. You'll also notice that your max Oxygen has ticked up to a much healthier 75 seconds!

How to craft a High Capacity Air Tank (Requires Lithium)

The next upgrade for your Oxygen meter is a High Capacity Air Tank. But to unlock it, you first need to find the recipe data card.

From the Lifepod, swim away at a 210-degree angle on your compass. Around 300 metres away, at 80m depth, you'll come across a wreckage. Enter the wreckage from the near side, and on the table to your left you'll find the High Capacity Air Tank recipe data card!

The player in Subnautica 2 approaches an underwater wreckage containing a High Capacity Air Tank recipe data card.

The player in Subnautica 2 approaches an underwater wreckage containing a High Capacity Air Tank recipe data card.

Image credit: RPS/Unknown Worlds

The player in Subnautica retrieves the High Capacity Air Tank recipe data card from a wreckage underwater.

Image credit: RPS/Unknown Worlds

Before you head home, swim over to the table just outside the wreckage. This table has a single piece of Lithium on it - an otherwise hard-to-find resource which you'll need to craft the High Capacity Air Tank.

The player in Subnautica 2 approaches a table in a wreckage underwater. The table has a single piece of Lithium on it.

This one Lithium is all you need... | Image credit: RPS/Unknown Worlds

Once you have the recipe, head back to base. The materials you need to craft the High Capacity Air Tank at the Fabricator are:

You can use your current Standard Air Tank for this upgrade, so there's no need to craft a new one. However, the Lifepod Fabricator isn't good enough to craft the High Capacity Air Tank. So, you will need to have unlocked the Habitat Builder tool and created your own base with its own Fully Functional Fabricator.

How to unlock the Habitat Builder...

You'll need to find and scan two Habitat Builder tools to unlock it for yourself. The first can be found beneath the Metal Salvage at the bottom of the cave hole on the east side of the Lifepod. The second can be found atop the crate by Anita's Blackbox and the giant Angel Comb plant, around 200m north. There are others, but these two are very easy to reach.

Once you've got your own Fabricator, all you need is 1x Plasteel Ingot. Plasteel Ingots are crafted in a Processor, so make yourself a Processor out of 2x Titanium, 1x Mild Acid, and 1x Copper Wire. Then you can use the Processor to craft a Plasteel Ingot out of 2x Titanium and 1x Lithium.

How to unlock the Processor...

You only need to find and scan one Processor in the world to unlock it. Multiple can be found inside the Old Habitat, a wreckage around 350 metres north of the Lifepod. If you have it, you can follow Wu's Blackbox signal straight to the Old Habitat.

Lithium is mainly found around Thermal Vents in the extremely hot biome to the far east, but you need the Heat Tolerance Adaptation to survive there. Thankfully, if you followed the above instructions, you'll have picked up that piece of Lithium on the table outside the wreckage where you found the recipe data card!

Use that Lithium to craft the Plasteel Ingot in the Processor. Once that's done, you can craft the High Capacity Air Tank in your Fabricator, and watch as your max Oxygen supply increases to a mighty 120 seconds.

How to craft a Rebreather

The final piece of equipment you need is the Rebreather. This mask, as I previously mentioned, counteracts the Oxygen consumption penalties which apply at certain depths, allowing your Oxygen to tick down at a steady 1 point per second at any depth.

Before you can craft a Rebreather, you need to find and scan it in the world. From the Lifepod, head 330 metres south-southeast, into the neighbouring biome with all the rocky pillars. You'll come across an area of the ground littered with wreckage, and inside a crate in the centre of the wreckage (right next to the Dive Elevator), you can find and scan the Rebreather.

The player in Subnautica 2 swims above an area of underwater wreckage strewn about the seabed.

The player in Subnautica 2 uses their Scanner tool to scan a Rebreather inside a crate amid some underwater wreckage.

Image credit: RPS/Unknown Worlds

Back at base, you can now craft a Rebreather from the following materials:

Fiber Mesh is made from 2x Fiber and 1x Strong Acid. Fiber is easy - just craft it from Fibrous Pulp, which you can gather using your Multitool from most organic matter in the world. Strong Acid is made in the Processor from Necrolei Cysts, which can be found 300m north-northwest of the Lifepod.

As for System Chips, they're made from 1x Wiring Kit and 2x Quartz. The only difficult part about this is the Silver you need to craft a Wiring Kit, but again, check out our guide on how to get Silver for all the information you need.

That's all you need in order to upgrade your max Oxygen supply for further, deeper, and longer trips away from your Lifepod in Subnautica 2. As you'll no doubt have seen, this process requires you to unlock a fair few tools and structures using your Scanner. If you're struggling to find everything you need, look no further than our massive database of all Databank entries in Subnautica 2!