Here is the full list of all 12 ABZU achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Discover those that lurk in the abyss.
Ride the Great White Shark.
Discover the polar region.
Add all secret shells to your collection.
Complete the adventure.
Witness predation while meditating.
Burst 15 fish schools in the jetstream.
Leap from the water.
Perform a flip while riding a creature.
Breach the water on the back of a blue whale.
Release fish from all the hidden pools.
Find all the meditation statues.