Witcher 3 Ironsides’ Treasure Walkthrough
Start Location: This is found on a small island in the centre of the ocean to the southwest of Ard Skellig. Locate the largest of the islands between the island of Faroe (to the southwest – the ‘Harviken’ fast travel marker is roiughly south of the target island) and Ard Skellig. Just north of this is a small chain of three islands with a hidden treasure marker.
Upon arriving at the Hidden Treasure marker, fight off any Sirens in the immediate area before looking for an overturned boat in a small depression between a pair of the interconnected small islands. Use Geralt’s Witcher Sense to locate the nearby corpse.
Upon looting the body you’ll receive a Notes about Treasure. Read the Notes about Treasure item in the Key Items section of the inventory. This will trigger the ‘Ironsides’ Treasure’ side-quest.
Make your way to the objective marker out in the water to the east of the Hidden Treasure location. Here a search area will open up around a sunken viking longship on the sea bed. Dive underwater and search floor surrounding the sunken ship with Witcher Sense to find a glowing red chest.
Loot this chest here to complete the side-quest. It contains a sum of Florens, a piece of gear or two and some other lootables.