How to Increase Oxygen Supply and Dive Deeper in Subnautica 2

Why Oxygen Is Your Biggest Limit

Oxygen is the single most important survival resource in the early and mid game of Subnautica 2. Your base oxygen supply is only 45 seconds, which limits how deep you can dive before drowning. Increasing your oxygen capacity and learning oxygen management strategies are essential for exploring deeper biomes. This guide covers every method to extend your dive time.

Oxygen Tanks: Your Primary Upgrade

Oxygen tanks are the most direct way to increase your oxygen supply. Each tier adds more reserve oxygen:

Always equip the best tank you can craft. The Ultra High Capacity Tank more than triples your base dive time, which is a game-changer for mid-depth exploration.

Vehicles as Oxygen Sources

Vehicles provide a mobile oxygen refill station. When you enter a Seamoth, Prawn Suit, or Cyclops, your oxygen refills instantly. This turns any vehicle into a breathing buffer:

• Seamoth: refills oxygen on entry. Park it near your dive site and return for air.
• Prawn Suit: same oxygen refill, plus depth protection for deep dives.
• Cyclops: a full mobile base with unlimited oxygen while inside.

The strategy is to dive out of your vehicle, explore until your oxygen is low, then return to the vehicle to refill. This effectively gives you unlimited dive time at any depth your vehicle can reach.

Pipes and Bases as Oxygen Stations

For early exploration before you have vehicles, use oxygen pipes. Pipes connect a floating surface buoy to your location underwater and pump air down. Lay a pipe line along your dive route to create an underwater air supply chain. This is cheap and effective for reaching 50-100 m depths early in the game.

Alternatively, build a small pipe base or a foundation with a hatch at your target depth. Any habitable structure provides oxygen when you enter it. A multipurpose room at 100 m becomes a refill station for deeper exploration.

Advanced Oxygen Strategies

• Dive in stages: Descend in 30-second increments, returning to your vehicle or pipe between stages.
• Use the rebreather: The rebreather removes the depth-based oxygen consumption penalty, making deep dives far more efficient. Craft it as soon as you unlock the blueprint.
• Swim efficiently: Use swim charge fins or the seaglide to move faster, spending less oxygen per meter of travel.
• Watch your depth: Below 100 m without a rebreather, oxygen drains faster. Plan your route to minimize time at extreme depths.
• Carry a spare tank: Some players swap tanks mid-dive, though this is risky and not recommended for beginners.

Oxygen Upgrade Checklist

Follow this progression to maximize your dive time:

1. Craft a Standard Oxygen Tank immediately.
2. Build a Seamoth for mobile oxygen refills.
3. Upgrade to the High Capacity Oxygen Tank.
4. Craft the rebreather to remove depth penalties.
5. Upgrade to the Ultra High Capacity Tank.
6. Use the Cyclops for unlimited deep-sea oxygen.