Here is the full list of all 18 Subnautica trophies - there are 1 bronze, 7 silver, 9 gold and 1 platinum.
Collect all other trophies
Create and deploy a time capsule
Launch the neptune rocket
Build a habitat
Find the Degasi habitat in the jellyshroom caves
Hatch and release a Cuddlefish
Cure the infection
Find the Primary Containment Facility
Repair the Aurora Reactor
Find the Thermal Plant
Find the Disease Research Facility
Find the Enforcement Platform
Find the Degasi habitat in the deep grand reef
Build a prawn suit
Build a cyclops
Build a seamoth
Find the Degasi habitat on the floating island
Dive for the very first time.