Increasing your O2 capacity is one of the first things you'll want to do in Subnautica 2. After all, it gets a bit annoying having to constantly resurface to gulp in air when you're trying to accomplish basic tasks. Your overall oxygen level is the game's real progression system, determining how deep you can dive and what rare resources are in your reach.
There are many different methods to boost your O2 and punch above your weight when under the sea, so here's how to acquire and use each of them.
