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