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