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