Inside the treasury of every active Sea Fort is a pile of loot! Unfortunately, these treasuries are locked! To open one, you’ll have to defeat waves of Phantoms, vanquish the Captain of the Fortress, and acquire the Fortress Treasury Key. You see, only a Fortress Treasury Key can open the treasury and give you access to the gold it holds!
How to get a Fortress Treasury Key
To get the Fortress Treasury Key, you’ll need to defeat a Captain of the Fortress. Upon defeat, a Captain of the Fortress will drop a Fortress Treasury Key.
You can only find a Captain of the Fortress on the eighth and final wave of an active Sea Fort. There are six different Sea Forts across the Sea of Thieves. If the Sea Fort has flags raised and is glowing green, you’ll know it’s active and ready to be pillaged.
Sail to the active Sea Fort, defeat seven waves of Phantoms, and you’ll finally face off against the Captain of the Fortress during the eighth wave. Defeat the captain, get the key, and the treasury is yours!

More about Sea Forts!
If you want to know more about Sea Forts, check out our guide on them here. We go over the difference between active and inactive Sea Forts, how long a Sea Fort reset timer is, and much more!