An example exterior of a skeleton fort.

Skeleton Forts or Fortress Raids are located at Strongholds with a Skull cloud above them in the Sea of Thieves universe. Only one can be active at a time where every player in the game has a chance to take its riches deep within.

Skeleton Clouds

A Skull shaped cloud that looms over a fortress. This is an indicator that a fortress is active and be raided, however a moving Storm may obscure it.


When active, the fort's defenses are manned by Skeletons and will open fire on any ship in the vicinity. Compared to an island's defenses, the volume of fire is higher from fortresses so navigating between shots or lining up a well place cannonball is a must to avoid taking too much fire.

Once docked, Pirates are expected to fight both the intial wave of defenders and subsequent ones contain one type of skeleton. The waves' lengths compose of 10 swarms which must be defeated before the next one begins.

When the final wave begins, the Skeleton Captain spawns and acts as the boss. When the captain is defeated, the cloud dissipates and the Vault Key can be used to open the Vault and the loot now able to be taken and sold.

Due to the intensity of the fighting, it is better suited for crews although it is possible for Fortresses to be cleared with only 1-2 or two players however the challenge is greater in that way.

The interior of a fortress.


  • After disabling the towers, it is advisable to park your ship broadside towards an opening to the fort, that way you will be able to fire upon any hostile vessels coming into the vicinity and also quickly launch back into the fray after spawning though one should remain to watch out for any other ships and maintain a spawn point for the other players.
    • In the event of other ships trying to stop your attempts, using the cannon towers and the keep's own weapons can be really beneficial. The steady platforms give pirate defenders an edge over attackers, who'd have to compensate for their vessel's movements to land hits.
  • Explosive barrels and barrels containing supplies litter the island and can be used to your advantage, the former being useful to clear out packs of enemies or to do serious damage towards bosses.
  • The Skeleton Captain is the boss of the fort and is very powerful. Defeat the captain with either explosive barrels or joust between his attacks and his Skull Key is yours for the taking, where loot can be found in an underground chamber below.
  • It is also possible to avoid damage from the coastal defenses with unpredictable steering. A keen helmsman can eliminate any possible hits by moving in a salom pattern, which helps throw off the AI's leading attempts. Moving in close enough to a spot where the cannons cannot reach is also advised to avoid any shrewd skeletons from harrasing your vessel during the raid.


Defeating the Skeleton Captain will result in a key being dropped and subsequently have the ability to open the fort's vault where many Treasures await. There will be more than 4 chests in the vault, so you'll need to pick and choose which to carry out, or plunder the vault quickly before other crews arrive to reap the spoils.

An example of a key unlocking a vault.

It should be noted that once the vault is open, any player in the world can access it, and any contents inside.

The interior of a vault.

Possible Skeleton Fortresses/Raids

Name Coordinates Region
Keel Haul Fort C-6 The Shores of Plenty
Hidden Spring Keep I-8 The Shores of Plenty
Sailor's Knot Stronghold E-14 The Shores of Plenty
Kraken Watchtower L-6 The Wilds
Shark Fin Camp P-5 The Wilds
Skull Keep Q=9 The Wilds
Old Boot Fort L-14 The Ancient Isles
Lost Gold Fort H-17 The Ancient Isles
The Crow's Nest Fortress 0-17/18 The Ancient Isles
Molten Sands Fortress Z-11/12 The Devil's Roar
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