How to Increase Oxygen in Subnautica 2 — Every Tank, Upgrade & Trick
Never drown again. Every oxygen tank upgrade, Rebreather, Oxygen Tunic locations, Air Bladder tricks, and how to maximize your dive time at every depth.
- •Standard Air Tank (75 O2) → High Capacity (~100) → Ultra High Capacity (~150)
- •Oxygen Tunics are blue bubble plants that refill O2 without surfacing — look for them everywhere
- •The Rebreather at 200m+ conserves oxygen — mandatory for deep Karakorum exploration
Every Way to Get More Oxygen
Running out of air is the #1 cause of death in Subnautica 2. Here's every way to stay underwater longer.
Oxygen Tank Upgrade Path
| Tier | Tank | Oxygen Pool | Materials | |------|------|------------|-----------| | 1 | Standard Air Tank | 75 | 2× Titanium, 1× Rubber, 2× Silver | | 2 | High Capacity Air Tank | ~100 | 1× Standard Tank + 1× Plasteel Ingot | | 3 | Ultra High Capacity Air Tank | ~150 | 1× High Capacity + 3× Troilite + 3× Atacamite |
Craft priority: Standard Tank should be your third craft (after Multitool and Scanner). Upgrade to High Capacity before entering Karakorum. Ultra High Capacity is late-game, requires Troilite from Metal Farms (300m+).
Rebreather, Mandatory Below 200m
| Material | Effect | |----------|--------| | 2× Fiber Mesh, 1× System Chip | Reduces oxygen consumption at depth |
Without the Rebreather, oxygen drains faster below 200m. This isn't optional for Karakorum exploration, it's mandatory. Craft it before your first Karakorum expedition.
Oxygen Tunics, Free Air Underwater
Blue bubble plants found in nearly every biome. Swim into the bubbles they emit to fully refill your oxygen without surfacing. Learn to spot them from a distance, they glow faintly and emit a steady stream of bubbles upward.
Best locations for Oxygen Tunics:
- Jelly Barrens (abundant)
- Old Habitat entrances
- Coral Gardens near biome transitions
Air Bladder, Emergency Oxygen
| Materials | Effect | |-----------|--------| | 2× Titanium, 1× Rubber | Instantly restores 25 O2 + rapid ascent to surface |
Craft one early and keep it on your hotbar. The Air Bladder auto-refills every time you surface. It's not for regular use, it's for emergencies when you're deep and your oxygen hits zero.
Pro tip: Use the Air Bladder BEFORE your screen starts going dark. The 25 O2 restore takes a second to kick in.
Oxygen Capacity by Depth Milestone
| Depth | Minimum Setup | Recommended Setup | |-------|-------------|------------------| | 0-30m | No upgrades needed | Standard Air Tank | | 30-100m | Standard Air Tank (75) | Standard + Air Bladder | | 100-200m | High Capacity (~100) | High Capacity + Rebreather | | 200-350m | High Capacity + Rebreather | Ultra High + Rebreather | | 350m+ | Ultra High (~150) + Rebreather | Ultra High + Rebreather + Tadpole nearby |
Related Guides
This guide was compiled from multiple public sources. We cross-reference with 3+ sources before publishing.
More Subnautica 2 Guides
Subnautica 2 Adaptive Measures Update — All New Biomods, Biolabs & Creature AI Changes
Subnautica 2's first major Early Access update is here. 6 Biomods, 2 new Biolabs, overhauled creature AI, sprinting, FOV slider, and a roadmap for what's next.
10 Best Survival Games Like Subnautica 2 to Play in 2026
Love Subnautica 2? Here are 10 more survival games with deep exploration, base building, and terrifying creatures. From the original Subnautica to Valheim, ranked by similarity.
Subnautica 2 — 12 Things You Should Stop Doing Immediately
Some habits in Subnautica 2 are actively making your life harder. Stop doing these 12 things and you'll save hours of frustration.