The Moon Tablets are ancient tablets that appear in the Wii/PlayStation 2 version of Sonic Unleashed, and are needed to access new stages in the game. Created in ancient times, the Moon Tablets serve as a means for their user to open the doors with a moon symbol inside their respective Gaia Gates which lead to certain areas on the continent.
In gameplay, the Moon Tablets unlock the local continent's Night Stages where Sonic the Werehog is playable. Despite there being seven Gaia Gates spread across the world, only six Moon Tablets exist, since Mazuri lacks a Night Stage.
Each of the Moon Tablets are designated to a specific Gaia Gate, and as such, a Moon Tablet cannot be substituted for another Gaia Gate other than its own.
In the game's story, most of the Moon Tablets lie in the possession of one of the people from the local village, who are usually the guardians of the Gaia Temples or someone associated with them. In order to obtain a Moon Tablet for the local Gaia Gate, Sonic must talk to a specific person found on the same continent and they will hand it over to him. In some cases, obtaining the Moon Tablet will reveal the local Gaia Gate on the map.