Locked doors are a Pet Simulator 99 tradition, and keys are the toll. Some keys arrive in halves that must be combined before use, which turns those locked rooms into a small collection quest, and spending keys levels the Keys Mastery, so even the unlocking itself is progression.
Group
Keys
Complete, usable keys and what each opens across the worlds.
Castle Key
Used to open the Castle in Area 3.
- Rarity
- Legendary
- How to get
- Reward after rebirthing once.
Prison Key
Used to open the Prison Chest.
- Rarity
- Legendary
- How to get
- Random drop from breakables, more likely in the Prison World.
Crystal Key
Used to open the Crystal Chest.
- Rarity
- Legendary
- How to get
- Created by combining its two halves. Also a possible item in The Forever Pack.
Hacker Key
Used to open the Hacker Chest.
- Rarity
- Legendary
- How to get
- Random drop from breakables, more likely in the Hacker World.
Tech Key
Used to open the Tech Chest.
- Rarity
- Mythical
- How to get
- Created by combining its two halves. Also a possible item in The Forever Pack.
Backrooms Key
Used to open backrooms rooms during Backrooms Event 2024. (Key removed as the event has ended)
- Rarity
- Mythical
- How to get
- -
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
- How to get
- -
Treasure Hideout Key
Used to enter the Treasure Hideout minigame for 30 minutes.
- Rarity
- Exotic
- How to get
- Created by combining its two halves.
Void Key
Used to open the Void Chest.
- Rarity
- Exotic
- How to get
- Created by combining its two halves.
Secret Key
Used to enter in Secret Rooms.
- Rarity
- Exotic
- How to get
- Created by combining its two halves. Also a possible item in The Forever Pack.
Santa Key
Used to open Santa's Cottage during Christmas Event 2024. (Key now has no functionality as the event has ended)
- Rarity
- Exotic
- How to get
- Obtained after hitting 10 targets with a Snowball Launcher in area 9.
Golden Prison Key
Used to open the Prison Chest, with a 10x huge chance.
- Rarity
- Celestial
- How to get
- Created by combining 10 Prison Keys in Area #203 (Prison Yard). Also a random drop from breakables, more likely in the Prison World.
Deep Backrooms Key
Used to open deep backrooms rooms during Deep Backrooms Event 2024. (Key removed as the event has ended)
- Rarity
- Celestial
- How to get
- -
Fiesta Key
Used to unlock the locked egg in the Fiesta Maze Prize Room during Piñata Maze.
- Rarity
- -
- How to get
- Found in Fiesta Gifts or dropped while smashing the maze. Also in the Candy Pack and Marigold Pack.
Fiesta Boss Key
Used to open the secret boss room by the final Fiesta boss during Fiesta Forever.
- Rarity
- -
- How to get
- Boss 3 drops it whole, and Bosses 1 and 2 drop halves that combine into it. Also in the Marigold Pack.
Lucky Titanic Key
Used to open the Titanic Chest during Lucky Block Blitz.
- Rarity
- -
- How to get
- Drops straight from Lucky Blocks.
Lucky Gargantuan Key
Used to open the Gargantuan Chest during Lucky Block Blitz.
- Rarity
- -
- How to get
- Drops straight from Lucky Blocks.
Group
Key Halves
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
- How to get
- Random drop from breakables, gift bags and other rewards. Merchants may sell it.
Crystal Key: Lower Half
Used to combine with the upper half to create a Crystal Key.
- Rarity
- Epic
- How to get
- Random drop from breakables, gift bags and other rewards. Merchants may sell it.
Tech Key: Upper Half
Used to combine with the lower half to create a Tech Key.
- Rarity
- Legendary
- How to get
- Random drop from breakables, gift bags and other rewards.
Tech Key: Lower Half
Used to combine with the upper half to create a Tech Key.
- Rarity
- Legendary
- How to get
- Random drop from breakables, gift bags and other rewards.
Treasure Hideout Key: Upper Half
Used to combine with the lower half to create a Treasure Hideout Key.
- Rarity
- Epic
- How to get
- Random drop from breakables, and a reward for completing ranks.
Treasure Hideout Key: Lower Half
Used to combine with the upper half to create a Treasure Hideout Key.
- Rarity
- Epic
- How to get
- Random drop from breakables, and a reward for completing ranks.
Void Key: Upper Half
Used to combine with the lower half to create a Void Key.
- Rarity
- Mythical
- How to get
- Random drop from breakables, gift bags and other rewards.
Void Key: Lower Half
Used to combine with the upper half to create a Void Key.
- Rarity
- Mythical
- How to get
- Random drop from breakables, gift bags and other rewards.
Secret Key: Upper Half
Used to combine with the lower half to create a Secret Key.
- Rarity
- Mythical
- How to get
- Random drop from breakables, gift bags and other rewards.
Secret Key: Lower Half
Used to combine with the upper half to create a Secret Key.
- Rarity
- Mythical
- How to get
- Random drop from breakables, gift bags and other rewards.
Halves, wholes, and where they lead
Several 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.
FAQ
How do key halves work in Pet Simulator 99?
Some keys drop as an upper and a lower half. Combine both halves to create the usable key, and check trading if you are stuck holding one half, since halves circulate between players.
What do Secret Keys open?
The game's secret rooms, which also require Rebirth 3. The rebirth grants access; the key opens the specific door.
What is Keys Mastery?
A mastery track leveled by using keys. It improves key-related rewards, which is a quiet argument for opening doors instead of stockpiling keys.
