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