Follow the Degasi
Uncommon18.6%ObjectiveOptional
Find the Degasi habitat in the jellyshroom caves
The jellyshroom caves are quite near where you start the game, down from the Safe Shallows. There's a base about 300m deep. Inside the base, find and use the PDAs within to unlock the achievement - the PDA you'll need is in the top part of the central area of the base.