Here is the full list of all 17 Subnautica achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Launch the neptune rocket
Create and deploy a time capsule
Hatch and release a Cuddlefish
Build a cyclops
Build a prawn suit
Repair the Aurora reactor
Cure the infection
Find the Degasi habitat on the floating island
Find the Primary Containment Facility
Build a seamoth
Find the Thermal Plant
Build a habitat
Find the Enforcement Platform
Find the Disease Research Facility
Find the Degasi habitat in the deep grand reef
Find the Degasi habitat in the jellyshroom caves
Dive for the very first time