All 23 Keys in Pet Simulator 99

Locked doors are a Pet Simulator 99 tradition, and keys are the toll. Most keys arrive in halves that must be combined before use, which turns every locked room into a small collection quest, and spending keys levels the Keys Mastery, so even the unlocking itself is progression.

Pet Simulator 99 collection

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Choose a sectionKeys (13)Key Halves (10)

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Keys

13 items

Complete, usable keys and what each opens across the worlds.

Castle Key

Used to open the Castle in Area 3.

Rarity

Legendary

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Prison Key

Used to open the Prison Chest.

Rarity

Legendary

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Crystal Key

Used to open the Crystal Chest.

Rarity

Legendary

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Hacker Key

Used to open the Hacker Chest.

Rarity

Legendary

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Tech Key

Used to open the Tech Chest.

Rarity

Mythical

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Backrooms Key

Used to open backrooms rooms during Backrooms Event 2024. (Key removed as the event has ended)

Rarity

Mythical

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Haunted Backrooms Key

Used to open the Haunted Backrooms during Halloween Event 2024. (Key now has no functionality as the event has ended)

Rarity

Mythical

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Treasure Hideout Key

Used to enter the Treasure Hideout minigame for 30 minutes.

Rarity

Exotic

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Void Key

Used to open the Void Chest.

Rarity

Exotic

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Secret Key

Used to enter in Secret Rooms.

Rarity

Exotic

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Santa Key

Used to open Santa's Cottage during Christmas Event 2024. (Key now has no functionality as the event has ended)

Rarity

Exotic

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Golden Prison Key

Used to open the Prison Chest, with a 10x huge chance.

Rarity

Celestial

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Deep Backrooms Key

Used to open deep backrooms rooms during Deep Backrooms Event 2024. (Key removed as the event has ended)

Rarity

Celestial

Summary

A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Image	Name	Use	Rarity	Summary
	Castle Key	Used to open the Castle in Area 3.	Legendary	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Prison Key	Used to open the Prison Chest.	Legendary	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Crystal Key	Used to open the Crystal Chest.	Legendary	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Hacker Key	Used to open the Hacker Chest.	Legendary	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Tech Key	Used to open the Tech Chest.	Mythical	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Backrooms Key	Used to open backrooms rooms during Backrooms Event 2024. (Key removed as the event has ended)	Mythical	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Haunted Backrooms Key	Used to open the Haunted Backrooms during Halloween Event 2024. (Key now has no functionality as the event has ended)	Mythical	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Treasure Hideout Key	Used to enter the Treasure Hideout minigame for 30 minutes.	Exotic	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Void Key	Used to open the Void Chest.	Exotic	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Secret Key	Used to enter in Secret Rooms.	Exotic	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Santa Key	Used to open Santa's Cottage during Christmas Event 2024. (Key now has no functionality as the event has ended)	Exotic	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Golden Prison Key	Used to open the Prison Chest, with a 10x huge chance.	Celestial	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.
	Deep Backrooms Key	Used to open deep backrooms rooms during Deep Backrooms Event 2024. (Key removed as the event has ended)	Celestial	A complete key ready to open its lock, and one of the items that levels the Keys Mastery when spent.

Group

Key Halves

10 items

The upper and lower halves that combine into their finished keys. Collect both, then forge.

Crystal Key: Upper Half

Used to combine with the lower half to create a Crystal Key.

Rarity

Epic

Summary

One half of a key; combine both halves to forge the usable key.

Crystal Key: Lower Half

Used to combine with the upper half to create a Crystal Key.

Rarity

Epic

Summary

One half of a key; combine both halves to forge the usable key.

Tech Key: Upper Half

Used to combine with the lower half to create a Tech Key.

Rarity

Legendary

Summary

One half of a key; combine both halves to forge the usable key.

Tech Key: Lower Half

Used to combine with the upper half to create a Tech Key.

Rarity

Legendary

Summary

One half of a key; combine both halves to forge the usable key.

Treasure Hideout Key: Upper Half

Used to combine with the lower half to create a Treasure Hideout Key.

Rarity

Epic

Summary

One half of a key; combine both halves to forge the usable key.

Treasure Hideout Key: Lower Half

Used to combine with the upper half to create a Treasure Hideout Key.

Rarity

Epic

Summary

One half of a key; combine both halves to forge the usable key.

Void Key: Upper Half

Used to combine with the lower half to create a Void Key.

Rarity

Mythical

Summary

One half of a key; combine both halves to forge the usable key.

Void Key: Lower Half

Used to combine with the upper half to create a Void Key.

Rarity

Mythical

Summary

One half of a key; combine both halves to forge the usable key.

Secret Key: Upper Half

Used to combine with the lower half to create a Secret Key.

Rarity

Mythical

Summary

One half of a key; combine both halves to forge the usable key.

Secret Key: Lower Half

Used to combine with the upper half to create a Secret Key.

Rarity

Mythical

Summary

One half of a key; combine both halves to forge the usable key.

Image	Name	Use	Rarity	Summary
	Crystal Key: Upper Half	Used to combine with the lower half to create a Crystal Key.	Epic	One half of a key; combine both halves to forge the usable key.
	Crystal Key: Lower Half	Used to combine with the upper half to create a Crystal Key.	Epic	One half of a key; combine both halves to forge the usable key.
	Tech Key: Upper Half	Used to combine with the lower half to create a Tech Key.	Legendary	One half of a key; combine both halves to forge the usable key.
	Tech Key: Lower Half	Used to combine with the upper half to create a Tech Key.	Legendary	One half of a key; combine both halves to forge the usable key.
	Treasure Hideout Key: Upper Half	Used to combine with the lower half to create a Treasure Hideout Key.	Epic	One half of a key; combine both halves to forge the usable key.
	Treasure Hideout Key: Lower Half	Used to combine with the upper half to create a Treasure Hideout Key.	Epic	One half of a key; combine both halves to forge the usable key.
	Void Key: Upper Half	Used to combine with the lower half to create a Void Key.	Mythical	One half of a key; combine both halves to forge the usable key.
	Void Key: Lower Half	Used to combine with the upper half to create a Void Key.	Mythical	One half of a key; combine both halves to forge the usable key.
	Secret Key: Upper Half	Used to combine with the lower half to create a Secret Key.	Mythical	One half of a key; combine both halves to forge the usable key.
	Secret Key: Lower Half	Used to combine with the upper half to create a Secret Key.	Mythical	One half of a key; combine both halves to forge the usable key.

Halves, wholes, and where they lead

The majority of keys drop as upper and lower halves; combine both and the finished key opens its target, from the Castle in Area 3 to the Backrooms and the rebirth-gated secret rooms. Halves are tradable in most cases, so a missing half is a trade away rather than a wall.

Using keys well

• Secret Keys pair with Rebirth 3: the rebirth grants access rights, the key opens the door.
• Using keys levels the Keys Mastery, which improves key-related returns, so there is a small compounding benefit to opening rather than hoarding.
• Event keys (like the Santa Key) belong to their events; open their doors while the season lasts.