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