At the Coast of Wrecks, a large group of pirates have made camp here. You'll have to take out about 10+ pirates before it's safe to access the letter, Pirate's notes, lying on the mattress. Read it to start this quest.
The marker will point you to a location out in the water, northwest of where you got the letter. You can choose to go the long way, which will also take you by guarded treasure out in the waters, or ride along the coast north until you're almost level with the location.
However you reach it, know there's a few drowners in the area. Deal with them, then look to see a sunken ship. You want to be on the eastern side, as that'll have the way in to the treasure. Look for the stairs and swim through the hole to see the treasure chest to the right.
Journal entry Edit
Geralt was, at his core, a curious individual. Thus when he found a letter on the coast of Velen, he sat down to study it right away...
Yesterday we found a silver basin and a ruby brooch on the bottom. Means Queen Zuleyka's treasure really is somewhere around here. Maybe in the hold of one of the wrecked ships off the west coast - but we can't check them at the moment, waves are too high. We'll have to wait till the seas calm. We're pitching camp.
Geralt followed the clues in the notes and recovered the sunken treasure.
- Read the letter you found.
- Find the sunken treasure using your Witcher Senses.