Quick answer
Use environmental oxygen first: Oxygen Tunics, Bloom Sap funnels once cleared, and cave air pockets can stretch early dives. Carry Air Bladders for panic returns, unlock Oxygen Control when you can, then craft the Standard Air Tank once you can spare Silver, Titanium, and Rubber. Treat the large oxygen tank blueprint as a route, not a quick grab: the video run spends oxygen on approach, scanning, and the return before the recipe screen appears.
Field notes for safer O2 runs
A scan route is slower than a mining route
Mining keeps you moving. Scanning makes you hover in one spot, often with your camera pointed away from the exit. Give scan routes more oxygen than they look like they need.
Do not spend Silver before checking the next recipe
Silver is easy to burn on electronics. If the Standard Air Tank is your next real upgrade, hold enough material back before crafting side pieces.
The large tank run starts before the door
In the P3 route footage, the pressure is already visible before the recipe UI: deep approach, low-O2 cave movement, and a structure stop all happen before the large oxygen tank screen. Plan the return before chasing the upgrade.
Treat Air Bladders like insurance
They are not glamorous, but they turn a bad cave turn into a story instead of a reload. Carry one until the route feels boring.
Video route stills
Frames from the P3 Bilibili route show why the tank upgrade is an oxygen-planning problem before it is a crafting problem.
Deep approach before the reward
At roughly 5:08, the route is already around 86 m with only 23 O2 showing. That is a turn-back warning unless you already know the exit chain.
Bilibili P3 route frame
Low O2 plus route work is the danger state
At roughly 10:10, the player is near an oxygen source but already down to the high 20s. Treat this as proof that refill points still need a clean route plan.
Bilibili P3 route frame
Recipe screen after the route is solved
At roughly 15:30, the large oxygen tank recipe is visible at a station. The important lesson is the prep: the upgrade screen comes after the deep route and structure work.
Bilibili P3 route frameVisual notes and source media
Original route art
Abyss Guides uses original chibi deep-sea art for page visuals instead of copying wiki screenshots or fan uploads.
Source: Abyss Guides original artwork
Official Subnautica 2 gameplay trailer
Use the trailer for mood, vehicles, and biome context. Do not treat trailer scenes as exact farming coordinates.
Source: Official Subnautica YouTube embedEarly O2 route
Use free oxygen before crafting
Do not treat every short dive as a gear problem. Oxygen Tunics, Bloom Sap funnels, and cave air pockets can keep a route alive while you are still poor on materials.
Carry Air Bladders
Air Bladders are still worth carrying after you know the area. They buy time, help with fast returns, and forgive one bad turn in a cave.
Craft the Standard Air Tank
The first permanent O2 upgrade is the point where caves stop feeling like a coin flip. Silver is usually the annoying part, so pair this page with the Silver route.
Scout the large tank route before committing
The large oxygen tank blueprint route asks for more than raw swimming time. Mark the entrance, confirm a refill or return cue, then go for the station or scan target on the committed run.
Budget extra O2 for scanning
Fragments, stations, wreckage, and marine-life scans all ask you to stay still. Treat scan routes as slower routes, not as normal resource loops.
Unlock Oxygen Control
Oxygen Control is useful when you scan, inspect wreckage, or hover around a point of interest. It is not flashy, but it removes pressure from slow tasks.
O2 planning card
Step 01
Borrow air
Use tunics, funnels, and pockets to finish short dives before upgrades.
Step 02
Carry backup
Air Bladders turn a bad cave turn into a recoverable mistake.
Step 03
Upgrade tank
Spend Silver on the Standard Air Tank once the route starts pushing deeper.
Oxygen options
| O2 method | Best use |
|---|---|
| Oxygen Tunics | Emergency oxygen while you are still learning the nearby biomes. |
| Bloom Sap funnels | Route extender after clearing the blockage around them. |
| Cave air pockets | Useful midpoint resets when you are mapping a cave loop. |
| Air Bladders | Portable oxygen and a faster return toward the surface. |
| Standard Air Tank | First major permanent oxygen upgrade. |
| Large oxygen tank blueprint | A deeper route upgrade. Scout the path first, then return with spare O2. |
| Oxygen Control | Best when scanning or staying still underwater. |
| Scan routes | Scanner and Bioscanner work need a bigger O2 buffer than mining loops. |
Oxygen is progression
If a route feels impossible, the answer is usually not bravery. It is more oxygen, better landmarks, a shorter loop, or one Air Bladder you forgot to pack.
FAQ
How do you increase oxygen early in Subnautica 2?
Use environmental oxygen, carry Air Bladders, unlock Oxygen Control, and craft the Standard Air Tank when you have Silver, Titanium, and Rubber.
What blocks the first Air Tank upgrade?
Silver is the early bottleneck for many players. Get a repeatable Silver route before trying to brute-force deeper caves.
Are Air Bladders still useful after a tank upgrade?
Yes. A bigger tank helps, but an Air Bladder can still save a bad return path or a greedy scan.
When should I chase the large oxygen tank blueprint?
After the Standard Air Tank and a repeatable return route. If you cannot name the entrance, refill point, and exit cue, scout first and come back.