Velen’s western coast inThe Witcher 3flanks a flourishing trade route leading to Novigrad, seeing a constant stream of ships packed to the gills with riches pass by. Not content to let such wealth go untouched, the coast has claimed its fair share of unwary sailors and their cargo.

Related:The Witcher 3: Black Pearl Side Quest Walkthrough

You can help yourself to the lost goods in Treasure Hunt: A Costly Mistake, one of the many such side quests found on the coast. Like the other shipwreck-based treasure hunts, you’ll be dealing with drowners and the sea itself as you look for the sunken chest, which this guide will guide you to.

Where To Start Treasure Hunt: A Costly Mistake

This treasure hunt is on Velen’snorthwestern coast, near the Hangman’s Alley Fast Travel point.From there, follow the roadwest, going past an abandoned siteto reach the beach.

There are several more quests involving sunken ships. From Hangman’s Alley, you can easily reachTreasure Hunt: Sunken TreasureandTreasure Hunt: Queen Zuleyka’s Treasure,both leading you to yet more riches.

A screenshot of The Witcher 3’s map with an orange circle over a quest objective.

At the quest’s starting point, you’ll encountera pack of drownersthat you’ll have to kill before you’re able to search a recently created corpse slumped by a wrecked boat and a pile of rocks. It’ll behighlighted by Geralt’s Witcher Sensesand contains the key and letter central to the quest.

Where To Find The Chest

Your prize isn’t far away. You’ll have to swim out to sea where you will find a sunken boat in the shallows. Circle around the vessel, usingGeralt’s Witcher Sensesto find a chest in the sunken wreckage.

Opening the chest with your freshly stolen key willend the quest,rewarding you with the contents of the chest and a powerful sword.

A screenshot of Geralt’s Witcher Senses highlighting a body in red.

The chest willcontain Maugrim,asilver sword well-suited for defensive players.It will improve bothQuen and Yrden Sign Intensity,helping you keep monsters at bay with both Signs. It alsocomes with three rune slots,for your enchanting needs.

Next:The Witcher 3: Complete Guide And Walkthrough

A screenshot of Geralt’s Witcher Senses highlighting a chest in red.