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