Running out of oxygen is one of the most punishing early-game threats in Subnautica 2. Your starting supply of 45 seconds disappears fast, and while the Standard Air Tank raises that to 75 seconds, it still cuts dives short the moment you start pushing below the shallow shelf. The High Capacity Air Tank raises your oxygen capacity to 120 seconds, nearly doubling your time underwater and making deeper biome exploration far more manageable.
This guide covers the exact Datacard location, the free Lithium tip that saves you a frustrating resource hunt, and the full crafting steps for the High Capacity Air Tank.
High Capacity Air Tank in Subnautica 2?
The High Capacity Air Tank is a direct upgrade to the Standard Air Tank. It occupies the same equipment slot and takes your oxygen from 75 seconds to 120 seconds. Before you can craft it, you need a few things in place:
- A Standard Air Tank already crafted and in your inventory
- A base with a fully functional Fabricator (the Lifepod Fabricator cannot craft the HCAT)
- A Processor to craft the Plasteel Ingot required by the recipe
If you have not yet built the Standard Air Tank, you need 2x Titanium, 1x Rubber, and 2x Silver. Silver is the hardest material to track down for that recipe, so handle that step before heading out for the HCAT Datacard.
High Capacity Air Tank Datacard Location
The Datacard sits inside a wreckage approximately 290 to 300 meters southwest of your Lifepod. The wreckage entrance is at around 80 to 87 meters depth.
From the Lifepod, face southwest and swim in a straight line. You will cross the shallow shelf and reach a point where the sea floor drops into a sheer cliff. Fill your oxygen tank completely before you make the final push down. If you have already located the Great Jaw Clam Leviathan while exploring the regions and biomes of Proteus, the wreckage sits just before it on the same heading.
The wreck rests at a tilt on the cliff edge. Head to the lower end to find the entrance. Once inside, turn left immediately. The High Capacity Air Tank Datacard is on a table next to the “Twins” log.
Tip: A Flashlight makes navigating the interior much easier. If you have not grabbed one yet, do that before this dive. There is also an Oxygen Tunic past the wreckage near the Great Jaw pit. If your air is running low, swim to it and refill before entering the wreck.
Unlike many blueprints in Subnautica 2, the HCAT does not require scanning. Picking up the Datacard adds the blueprint directly to your inventory.
Lithium Location Near the Wreckage
Lithium is one of the rarest early-game resources in Subnautica 2, but you do not need to farm for it to craft the High Capacity Air Tank. There is a free piece sitting right next to the wreckage.
After collecting the Datacard, exit the wreck and look for a metal structure with a table at the center. A single Lithium chunk sits in a small coral shell on that table. Pick it up before you surface.
That one piece of Lithium is everything you need for the Plasteel Ingot. Larger Lithium deposits are found around Thermal Vents further east and near the Tadpole Pens, but you need the Heat Tolerance Adaptation to survive in those areas. For this craft, the table spawn is all you need.
How to Craft the Plasteel Ingot
The High Capacity Air Tank recipe requires one Plasteel Ingot, which you cannot make in a Fabricator. You need a Processor.
Processor recipe: 2x Titanium, 1x Mild Acid, 1x Copper Wire
Once your Processor is built and powered, craft the Plasteel Ingot:
Plasteel Ingot recipe: 2x Titanium, 1x Lithium
Titanium is one of the most available resources on the ocean floor, so sourcing two pieces should be straightforward at this stage of the game.
How to Craft the High Capacity Air Tank
With the Datacard collected and a Plasteel Ingot ready, head to your base Fabricator. The Lifepod Fabricator does not support this recipe.
High Capacity Air Tank recipe:
- 1x Standard Air Tank
- 1x Plasteel Ingot
You can use your currently equipped Standard Air Tank as the crafting material. Once you confirm the craft, your oxygen capacity immediately jumps to 120 seconds and the tank equips automatically into the correct slot.
With 120 seconds of air, you can start reaching areas that were previously too deep or too far to explore safely. If you want to keep your material supply stocked for future crafts, building a Metal Farm is one of the most efficient ways to stay topped up on rare ores without constant manual diving. Play Now!
