Subnautica 2 High Capacity O2 Tank Blueprint Location
In Subnautica 2, the High Capacity O2 Tank blueprint is found inside supply crates and data boxes scattered across the Twisty Bridges and the Kelp Forest biomes. You do not need a specific quest or tool to unlock it – just explore those areas thoroughly and scan the fragments you find. The tank itself is a direct upgrade to the Standard O2 Tank, increasing your oxygen capacity from 75 to 120 units, which is a major early-game survival boost.
Where Exactly to Look
The High Capacity O2 Tank blueprint is not tied to a single fixed location. Instead, its fragments spawn randomly inside the small, glowing supply crates that litter the seafloor and inside the larger data boxes that sometimes rest on rock ledges or inside wreckage. The two most reliable biomes for finding these crates are:
- Twisty Bridges – this biome is the starting area and has a high density of supply crates, especially near the large rock arches and along the sandy patches between the kelp stalks.
- Kelp Forest – the dense kelp areas to the north and west of the starting pod also contain many crates, often hidden under the kelp roots or inside small caves.
When you open a crate, there is a chance it will contain a High Capacity O2 Tank fragment. You need to scan three fragments to unlock the blueprint. The crates respawn after a few in-game days, so if you don’t find all three on your first sweep, return later or explore a different part of the same biome.
How the Blueprint and Scanning Work
In Subnautica 2, most equipment blueprints are obtained by scanning fragments with your handheld scanner. Fragments appear as glowing, holographic pieces of the item – for the High Capacity O2 Tank, they look like a small, metallic cylinder with a glowing blue core. To scan them, simply point your scanner at the fragment and hold the scan button until the progress bar completes. Each fragment you scan adds to your progress toward the blueprint.
The tank itself is crafted at the Fabricator once you have the blueprint. It requires:
- 1x Standard O2 Tank (which you already have from the start)
- 1x Titanium Ingot (crafted from 10 Titanium)
- 1x Glass (crafted from 2 Quartz)
The High Capacity O2 Tank is a direct upgrade – it replaces your standard tank in your inventory and gives you 120 units of oxygen instead of 75. This means you can stay underwater for about 60% longer before needing to surface or use a vehicle’s oxygen supply.
Why This Tank Matters Early On
Oxygen is the most limiting resource in the early game of Subnautica 2. With the standard tank, you can only dive to about 30–40 meters before you need to start heading back up. The High Capacity O2 Tank effectively extends your safe diving time, letting you explore deeper wrecks, gather more resources per trip, and reach the first major story locations without constant resurfacing.
It is especially useful for exploring the Twisty Bridges’ deeper sections, where you’ll find the first Alterra wreck and several important story items. Without the extra oxygen, you’ll be forced to make multiple trips, which is both time-consuming and risky because you might run out of air while trying to locate a specific crate or fragment.
Common Misconception: It’s Not in the Wrecks
A frequent mistake players make is assuming the High Capacity O2 Tank blueprint is found inside the large shipwrecks, like the one in the Twisty Bridges or the larger wreck in the Kelp Forest. While those wrecks do contain valuable fragments for other items (like the Seaglide and the Laser Cutter), they do not contain the High Capacity O2 Tank blueprint. The tank fragments only appear in the small supply crates and data boxes.
Another misconception is that you need a laser cutter or a propulsion cannon to reach the crates. In reality, most crates are in open water or on the seafloor, and you can reach them with just your starting gear. The only tool that helps is the Seaglide for faster travel, but it’s not required.
Alternative: The Ultra High Capacity O2 Tank
Later in the game, you can find the Ultra High Capacity O2 Tank blueprint, which increases your oxygen to 180 units. That blueprint is found in deeper biomes, such as the Deep Twisty Bridges and the Lilypad Islands. However, the High Capacity tank is the one you want early on because it’s cheap to craft and provides a massive improvement over the standard tank.
If you’re planning to explore deeper areas before you find the Ultra blueprint, the High Capacity tank is a solid middle ground. It’s also useful as a backup tank if you’re using a vehicle and want to switch to a lighter loadout.
Tips for Finding Fragments Faster
If you’re struggling to find all three fragments, try these strategies:
- Use the Seaglide to cover more ground quickly – it’s crafted with a Battery, Copper Wire, and Titanium.
- Search during the day – the glowing fragments are easier to spot against the sandy bottom.
- Check every crate you see, even if you think you’ve already searched that area – crates respawn after a few in-game days.
- If you’re playing on a save where you’ve already explored a lot, try heading to the far edges of the Kelp Forest – there are often crates tucked into the corners of the biome.
Remember that fragments are shared across the world – you don’t need to find all three in the same biome. If you find one in Twisty Bridges and two in Kelp Forest, that’s perfectly fine.
Frequently Asked Questions
Do I need a laser cutter to get the High Capacity O2 Tank blueprint?
No. The fragments are almost always in open supply crates or data boxes that are accessible without any tools. The only tool that helps is the Seaglide for faster travel, but it’s not required.
Can I find the blueprint in the starting pod area?
The immediate starting area (the safe shallows) has very few crates. You’ll need to swim out to the Twisty Bridges or Kelp Forest, which are adjacent to the starting biome.
How many fragments do I need to scan?
You need to scan three High Capacity O2 Tank fragments to unlock the blueprint. The game tracks your progress in the PDA under the ‘Blueprints’ tab.
Is the High Capacity O2 Tank worth crafting?
Yes, absolutely. It increases your oxygen from 75 to 120 units, which is a 60% improvement. It’s one of the most cost-effective upgrades in the early game, requiring only a few common resources.
Does the tank stack with other oxygen sources?
No. The tank replaces your standard tank and is the only oxygen source in your inventory. However, you can still use vehicles (like the Seamoth) which have their own oxygen supply.
What if I can’t find the fragments after searching for a long time?
If you’ve thoroughly searched both biomes and still haven’t found all three, try leaving the area and coming back after a few in-game days – crates respawn. Alternatively, check the deeper parts of the Twisty Bridges, as some crates are on the seafloor at depths of 50–80 meters.
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