What to do with · Valheim 1.0.17
What to do with Swamp Key
Partly covered in caked mud, it smells foetid.
It opens the Iron Gate of Sunken crypt. Nothing crafts or builds with it.
Weight 0.1Full Swamp Key page →
What it opens
Raids
On worlds with player-based raids, the items a player has picked up decide which raids can come to that player's base.
Having picked it up lets these come:A foul smell from the swamp..., The ground is shaking
Having picked it up stops these:The forest is moving...
Last resort: the Obliterator
Obliteratorturns any 10 items (stacks counted one by one) into 1 
Coal; the rest is lost.
Incinerator.Incinerate in the game code.
Where to get more Swamp Key
Dropped byThe ElderBlack Forest
Questions
›What is Swamp Key used for in Valheim?
It opens the Iron Gate of Sunken crypt. Nothing crafts or builds with it.
›Can you sell Swamp Key in Valheim?
No. Traders only buy items with a trade value, and Swamp Key has none. The 9 that do: Amber, Amber Pearl, Ancient Coin, Draumyx, Grimvarn, Solryth, Veydris, Ruby and Silver Necklace.
›Can Swamp Key go through a portal?
Yes, Swamp Key can be carried through a portal.
›Where do you get Swamp Key?
The Elder. Every source is on the Swamp Key page.
Source: recipes, building pieces, stations, altars, traders and the Obliterator in the files of Valheim 1.0.17 (2026-10-05), prefab CryptKey.