The 
Frozen Chest is a locked treasure block that generates once in every Pirate Shelter, the structure Aquamirae hides beneath the Ice Maze, and the only thing that opens it is a 
Frozen Key taken from the Ghost of Captain Cornelia.
It can’t be mined, it shrugs off explosions and a Piston won’t shift it, which is why the whole mod tends to funnel you toward that one boss fight. Everything the pirates were guarding ends up in here, and the 
Rune of the Storm the last 
Logbook keeps raving about is inside every single one of them.
This page covers where the Frozen Chest is, how the Frozen Key is used on it, and what tends to come out, with the odds worked from the loot table so you’ll know whether a second key is worth the trouble.
Where to Find the Frozen Chest
Frozen Chests only generate inside the Pirate Shelter, and each shelter holds exactly 1 of them. The shelter was dug by the pirate crew once their fort could no longer be heated, which is why it’s found under the seabed of the Ice Maze rather than on top of it. The way in is a vertical shaft, which you’ll drop down from a round entrance on the surface.
The Frozen Chest itself has been set into a wall of 
Blue Ice near the top of the wooden building, which means it can be reached before the lower floors have been cleared. You won’t want to open it until they have, though, for reasons covered further down.
It’s also the rarest thing the mod generates by a long way. Shelters are spaced much further apart than the Pirate Ships and Pirate Outposts you’ll keep running into, which makes finding one mostly a matter of covering ground along the ice and watching for that circular entrance.
Captain Cornelia doesn’t drop any kind of Map to it on this version, whatever the older guides might say. If cheats are enabled the locate command will point you at the nearest one, which saves a lot of wandering.
Shelters generate in The Maelstrom as well, as that whole dimension is built from the Ice Maze biome, which means a Frozen Chest can be found down there too if you’ve made the trip. Whichever side you’re on it looks the same, a Chest with its lid frozen into a block of ice and a padlock hanging off the front.
One thing worth knowing before you go down is what else is in there with it. A Pirate Shelter is guarded by a pack of Tortured Souls, an Eel placed down in the lower section, a single Evoker, and the usual Pillagers and Vindicators, which is far more than a ship or an outpost throws at you. The Frozen Chest isn’t going anywhere, which means the fight can come first.
Opening the Frozen Chest
The Frozen Chest is opened by right-clicking it while you’re holding a Frozen Key, and nothing else is accepted. Any other item does nothing at all, there’s no message and no animation. The key is only dropped by the Ghost of Captain Cornelia, and that means the route will always run through her.
Claim a Frozen Key
Dropped by the Ghost of Captain Cornelia
Cornelia has to be summoned with a 
Shell Horn, which comes from the captain of a Pirate Ship, and once she’s down she drops exactly 1 Frozen Key every time. She also leaves behind an enchanted 
Salvager Helmet and between 6 and 10 
Treasure Pouches, which means the fight tends to pay for itself before the key has even been used.
The Frozen Key can’t be crafted and doesn’t turn up in any 
Chest, and it has no other use in the mod. There’s no reason to hold onto it once you’ve found a shelter, as it never wears out and never expires.
Get Down to the Chest
Near the top of the shelter’s main chamber
Drop down the entrance shaft and work through the shelter until you’ve found the Frozen Chest, which will be set into the ice near the top of the building. The key survives everything, including dying on the way, as long as your items are picked back up, which means there’s no rush and no risk of it being used by accident.
Clear the room before you touch it. Opening the Frozen Chest turns it into an ordinary Chest, and an ordinary Chest is something a Vindicator will happily stand between you and while you’re trying to empty it.
Right-Click It With the Key
The key is used up and the loot is rolled
Right-click the Frozen Chest with the key in your hand and it unlocks on the spot, with an unlock sound, a burst of particles and the key gone from your inventory. What has actually happened is that the block has been replaced with an ordinary Chest facing the same way, which is then filled from the Frozen Chest loot table there and then.
Every Frozen Key is consumed when it’s used, and every Frozen Chest only ever opens once, since it stops being a Frozen Chest the moment it unlocks. Opening a second one means killing Cornelia a second time, which means another Shell Horn from another Pirate Ship captain.
Loot
The Frozen Chest loot table is built from 4 pools. The first is rolled 8 to 12 times and is where the 
Emeralds, 
Gold Ingots, 
Diamonds and 
Golden Apples come from, the second is rolled 1 to 3 times for enchanted weapons and Treasure Pouches, and the third is rolled once or twice for the relics.
The fourth pool is a single roll that only holds the Rune of the Storm. The odds below are worked across all of those rolls, so they’re the chance of seeing at least 1 of each item when you open the Frozen Chest.
Frozen Chest Contents
Rune of the Storm 
Emerald 
Gold Ingot 
Diamond 
Golden Apple 
Enchanted Golden Apple 
Treasure Pouch 
Iron Sword 
Bow 
Crossbow 
Iron Axe 
Totem of Undying 
Dagger of Greed 
Sea Stew 
Collectible Painting 
Collectible Painting 
Collectible Painting 
Collectible Painting The Rune of the Storm is the reason the Frozen Chest exists, and it’s the one thing you’re certain to get, since it sits in a pool of its own that always rolls. Around it the staples are generous, as 8 to 12 rolls on the first pool means you’ll almost always walk away with Emeralds and Gold Ingots.
Each Collectible Painting turns up about 15% of the time, and there’s a little over a 50% chance of getting at least 1 of the 4, which means a full set will take several chests. The enchanted Iron Sword, Bow, Crossbow and Iron Axe are rolled with treasure enchantments allowed, which means Mending can show up on them, as it can’t from an Enchanting Table.
Frequently Asked Questions
Inside the Pirate Shelter, the underground structure beneath the Ice Maze, where 1 is placed near the top of the main chamber. It’s the rarest structure the mod generates, so you’re looking for a round entrance on the surface of the ice with a shaft going down, or using the locate command with cheats on. Shelters in The Maelstrom have a Frozen Chest too.
Only from the Ghost of Captain Cornelia, who drops 1 every time she’s killed. She’s summoned by using a Shell Horn near open water in the Ice Maze, and the horn is dropped by the captain aboard a Pirate Ship. The Frozen Key can’t be crafted, traded for or found in any chest, and it’s used up when it opens a Frozen Chest.
No. The block has the same hardness and blast resistance as Bedrock, so it can’t be mined in survival, TNT and Creepers do nothing to it, and a Piston won’t move it. Right-clicking it with anything other than a Frozen Key also does nothing, without so much as a message. Creative mode is the only way past the lock.
Yes, every Frozen Chest holds exactly 1, because the rune sits in its own pool that always rolls once. Bear in mind that on Forge 1.20.1 the rune is a display item with no effect, whereas on the 1.21 NeoForge version it can be fitted to a weapon at a Smithing Table for a bonus in cold biomes. The Frozen Chest is the only place it generates on either version.
