Here is the full list of all 14 Submerged: Hidden Depths achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Collect all Diaries
Collect all Boat Boosts
Collect all Relics
Visit all Landmarks
View a Relic at the Home Base
Change Hair Style
Collect all Styles
Collect all Flowers
Finish the Campaign
Use all Lookouts
Change Body Style
Put a Flower in your hair
Change Boat Style
Collect all Creatures