The Planet Tablets are ancient tablets that appear on the Wii/PlayStation 2 version of Sonic Unleashed. These tablets replace the Gaia Keys, which are on the Xbox 360/PlayStation 3 version of the game.
Created in earth's ancient past, the Planet Tablets gain their users access to their respective continent's Gaia Temple by having them unlock the portals (called the Boss Gate) inside the Gaia Gate which lead to the vicinity of their respective temple. While there are seven Temples of Gaia in the world, only six keys are needed to be collected since no Gaia Gate is needed to reach the Gaia Temple in Eggmanland.
Each Planet Tablet is split in two; one daytime half (the one with the red jewel) and one nighttime half (the one with the blue jewel). One of each type is needed to form one Planet Tablet, and both halves has to originate from the same continent.
To unlock the Boss Gate, Sonic must collect each halves of the Planet Tablet and reassemble it. Each half is obtained after clearing the main stage on each continent, with the daytime half found in the main Daytime Stage and the nighttime half found in the main Nighttime Stage. The player then has to seek out the local Gaia Temple guardian, or someone associated with them, who can assemble the two halves into a Planet Tablet.
- The Planet Tablet for the Dark Gaia Phoenix is unnecessary as it is obtained after the battle.