Child of Poseidon achievement, apparently this is a rare achievement, but I'm glad I got it, did anyone have any issues finding all the underwater locations? (Mine was the shipwreck of Nestor
Assassin's Creed Odyssey - How to Breathe Underwater, Poseidon's Trident - Prima Games
Assassin's Creed Odyssey - All 42 Underwater Location Objectives - Child of Poseidon Trophy - YouTube