Here is the full list of all 38 Koa and the Five Pirates of Mara achievements.
Complete the tutorial.
Unlock the first map.
Unlock a small map.
Unlock every map in the game.
Get the first sunken treasure.
Get all the sunken treasures.
Meet Onzo five times.
Beat Taima in the race.
Escape from Ereti in the Navy.
Beat Mr. Ecco.
Complete the Mahla Temples.
Beat the Colossus.
Reach the peak of the Black Volcano.
Deactivate Elit Station.
Complete Grant Loom’s Lair.
Win a race against the pirate apprentices.
Win every race against the pirate apprentices.
Get a gold medal.
Get 15 gold medals.
Get every gold medal.
Find your first collectible.
Find every piece of fabric.
Find every pearl.
Find every piece of plastic.
Find every gear.
Buy an upgrade for the boat.
Buy every upgrade for the boat.
Buy a t-shirt for Koa.
Buy all the t-shirts.
Buy a backpack for Koa.
Buy all the backpacks.
Buy a Qälis expansion.
Buy all the Qälis expansions.
Pet the dog.
Go up to your roof on Home Island.
Dump the trash in a frog container.
Catch all 5 whales in the sea.
Find all 25 barrels in the sea