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