This guide will let you know how to get to the Inactive Lava Zone in Subnautica.
Starting from the coral tube sticking up out of the water, you will need to head northwest or 1-2 bumps to the right of the northwest until you reach the blood kelp french next to the northwestern mushroom forest biome.
It is recommended to have a prawn suit with an MK1 depth module, a high capacity O2 tank, a sea glide, a cyclops with an MK2 Depth module, extra power cells for your cyclops if you don’t have the thermal reactor module. You will also need a reinforced dive suit and a survival knife.
The main threats you will encounter in the inactive lava zone are the sea dragon Leviathan, you have to avoid them as best as you can, and the lava lizard you can kill using the stasis rifle and normal survival knife. You will also face the warper; if it warps you, you can attack it using your knife until it warps away, or you can run away from it.
There are also lava larva in the inactive lava zone, which will latch onto your vehicle/cyclops and drain its energy, but if it does, you can cut it off using the knife.
Once you’re in the lost river, you will need to look for a large drop that goes down to about 800m.
It is the drop that you’re looking for.
Once you’re down the drop and in an area that looks like this, you have to head to the path/entrance on the right, and you will end up in the Tree cove part of the lost river.
Once you’re in the tree cove, you have to go around the large tree, and you want to continue straight through the tree cove until you reach an area where you can descend into a large crevasse/cavern.
Once you reach a large cavernous area that looks like this, you will need to head to the right and continue through the path. You will eventually reach a large open area in the inactive lava zone.
Starting from the coral tube, you will need to head northeast or half a bump-1 bump to the fight of northeast until you reach a large drop with a large entryway in the bulb zone.
Once you reach the entryway, you have to continue through it until you reach a large hole in the lost river.
Once you’ve reached the large hole, you will need to go down the hole, and once you’ve gone down the hole, you will be in the inactive lava zone.