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