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.
Discover the polar region.
Ride the Great White Shark.
Complete the adventure.
Breach the water on the back of a blue whale.
Burst 15 fish schools in the jetstream.
Perform a flip while riding a creature.
Witness predation while meditating.
Leap from the water.
Release fish from all the hidden pools.
Find all the meditation statues.
Add all secret shells to your collection.