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.
Release fish from all the hidden pools.
Find all the meditation statues.
Complete the adventure.
Ride the Great White Shark.
Discover those that lurk in the abyss.
Witness predation while meditating.
Burst 15 fish schools in the jetstream.
Perform a flip while riding a creature.
Leap from the water.