This is just a short guide (a map) to show you where to find the vaults and the final reward.
Map
Vault 1 ~ 16 can be found on the map above
Vault 17 ~ 20 are hidden inside “The Forshaken Strand” area
All of them can be easily found at ground level inside the area with vault 20 located slightly above ground level.
Cross current location (Green Arrow) on the map above is where you will find the reward for completing all the vaults.
This weapon can be further crafted into the Legendary Weapons (requires for the achievement) at Tinkertown after you cleared the quests there.
By Meowish
