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