Running out of oxygen every 45 seconds is genuinely one of the most frustrating feelings in Subnautica 2. You’re inches away from that rare resource, that hidden cave, that amazing biome — and then your screen starts flashing. Sound familiar?
Here’s every method to boost your O2 and stay underwater longer, from the very first dive to deep-sea domination.
Table of Contents
All Oxygen Methods in Subnautica 2
| Method | O2 Boost | When Available |
|---|---|---|
| Oxygen Tunics (blue plants) | +45 (refill) | Early game |
| Air Bladder | +25 (consumable) | Early game |
| Standard Air Tank | +75 max capacity | Early-mid game |
| High Capacity Air Tank | Higher max capacity | Mid game |
| Portable Oxygen Generator | Continuous supply | Mid game |
| Oxygen Control Biomod | Slows O2 depletion | Early-mid game |
| Vehicles & Powered Bases | Full refill | Progression |
1. Oxygen Tunics — Your Early Game Lifeline
While exploring the vast underwater world, you may spot glowing blue plants called Oxygen Tunics. They create small air bubbles that you can approach to replenish your oxygen by +45. Always swim between them during dives — they’re essentially free breathing stations scattered on the ocean floor. Deltia’s Gaming
2. Air Bladder — The Emergency Escape Tool
An Air Bladder has two uses: it can quickly lift you to the surface, or you can use its stored air to replenish oxygen by +25, giving you another 15 seconds underwater. Craft one with 2x Titanium and 1x Rubber — and carry multiple. Deltia’s Gaming
3. Standard Air Tank — First Permanent Upgrade
The Standard Air Tank blueprint is available by default. To craft it, you need 2x Titanium, 2x Silver, and 1x Rubber. It increases your maximum oxygen to +75. Silver is your biggest challenge early on — find it near the Old Habitat and Camp One area. Yahoo!
4. High Capacity Air Tank — The Deep Dive Enabler
The High Capacity Air Tank comes from the Research Center/Alien Ruins. Grab the datapad at the entrance to unlock the blueprint. It requires 1x Standard Air Tank and 1x Plasteel Ingot, which is crafted via the Processor using 2x Titanium and 1x Lithium. GameSpot
5. Oxygen Control Biomod — The Silent Game-Changer
The Oxygen Control passive Biomod lowers your O2 consumption when you’re still — making it perfect for when you’re scanning or investigating something underwater. Activate it at the Biolab inside the Welcome Center (85m south-east of Lifepod). PC Gamer
6. Portable Oxygen Generator & Bases
The Portable Oxygen Generator costs 3x Titanium and 2x Lithium, requires 1x Basic Battery to function, and its oxygen level is refilled over time through electrolysis. Powered bases also restore oxygen instantly when you step inside — build small outpost bases during deep dives as breathing checkpoints. GameSpot
For more Subnautica 2 tips and gaming guides, head to Technosports.
FAQs
Q: How much oxygen do you start with in Subnautica 2?
You begin Survival Mode with just 45 oxygen, depleting at -1 per second underwater — crafting the Standard Air Tank raises this to 75.
Q: What is the fastest way to get oxygen in Subnautica 2?
Swim to glowing blue Oxygen Tunics on the ocean floor for an instant +45 refill, or use an Air Bladder for a quick +25 boost mid-dive.
