You start with just 20 inventory slots and five hotbar spaces in Subnautica 2, which you'll fill up in a matter of minutes. After that, you'll be juggling storage chests and trying to find any nook and cranny to stow all your junk. So, finding out how to increase your inventory size is a high priority early on.
The good news is that you can actually increase your inventory and your hotbar space, though it'll take a bit of work. While you're at it, I recommend building the Wakemaker and getting some O2 upgrades to make life easier.
