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