Armor (Enhanced): Below The Folly, Into The Lake

Between the village of Frischlow (to the south), and Fyke Isle in Lake Wyndamer (to the north) is a small island with the remains of a brick folly slowly sinking into the water. Beware of Drowners as you swim or take a boat there (if you find any underwater, introduce them to a crossbow bolt or two).

Just off the southern tip of the island where the majority of the brick ruins are, use your Witcher Senses to check underwater for a number of chests. The one shown here, around 15-20 feet below the water but close to the shore, is the one to loot.