Rainbow Stars are a special currency in Plants vs. Zombies: Garden Warfare 2 that were introduced in the Trials of Gnomus DLC. They are a variant of Stars, and are used to open special chests inside the Town Hall. The chest on the left (yellow) costs 10 Rainbows Stars to open; the chest on the right (blue) costs 30 Rainbow Stars to open; the chest in the middle (red) costs 50 Rainbow Stars to open. The player can hold a maximum of 50 Rainbow Stars at a time.
Rainbow Stars may normally be obtained in only two ways. The first, and main, way to earn Rainbow Stars is to enter the Mystery Portal inside the Town Hall, and complete events inside it. Doing this will give the player between 3 to 7 Rainbow Stars. The second way is to give 7 regular stars to the seagull inside the Town Hall, in exchange for just 1 Rainbow Star.
There is a third method, but only comes around periodically. There are special packs to get 10, 30, or 50 Rainbow Stars The packs are only available if you have room for their specified amount. For example, once you obtain 1 Rainbow Star, you cannot purchase the 50 Rainbow Star pack until you spend that star (and any others you may have received. This holds true for both of the other packs as well. Having greater than 20 or 40 Rainbow Stars will disable the purchase options for the 30 and 10 Rainbow Star packs, respectively.
- If the player obtains 25 Rainbow Stars by completing events inside the Mystery Portal, they will earn the Somewhere Over the Rainbow achievement.