The planet keys are a group of keys marked with the astrological symbols of planets that are used on their respective locks. The exceptions to this group are the Sun Key and the Zero Keycard, which although are not planets, are counted towards this group anyway for continuity purposes. The keys can take the form of either a physical key or that of a keycard. These keys are found in Nine Hours, Nine Persons, Nine Doors inside various escape rooms.
The Sun Key is found in a pipe in the Torture room.
This key is found in the Shower room inside the drain.
The lock is found in the gate near the Casino.
This key is found in the Laboratory inside one of the lockers.
This key is found in the 2nd class cabin behind the dog painting.
The lock is in the same area outside the cabins.
This key is found in the Operating room in a drawer on John's scale.
The lock is in the C Deck hallway. It leads back to the central staircase.
This key is found in the Kitchen inside the oven.
This key is found in the Study, inside the coffin.
0 Key Card
The card found in the Study, inside a drawer along with a photograph.
The lock is in the same room and opens the exit to the study.
- The Sun Key is the only key that is never used by Junpei, as the Sun Door is already unlocked.
- As Pluto was declared a dwarf planet in 2006, no Pluto Key is found in the game.