This article is about Galaxy Arena court in general. For information about the battle tournament stage from Mario Kart Wii
known as Galaxy Arena in Europe, see Galaxy Coliseum
Galaxy Arena is a galaxy-based court in Mario Tennis Open. It has objects from Super Mario Galaxy, such as Shrinking Tiles, a Launch Star, Star Bits, a planet from the Gateway Galaxy, a Black Hole, Turquoise, Red and Green Lumas, and the whole Comet Observatory in the distance. The special game Galaxy Rally is played on this court, where the Star Chips appear on the court, and the player needs to collect them by hitting the tennis ball at them. It is an unlockable stage, and it can be unlocked by completing the Final Cup in the Star Open Tournament.
The unlockable stage has differences to the one played in Galaxy Rally; it lacks disappearing green platforms and it takes place in an another location. Also, it has max bounce and max speed. There are two varieties to this court: the Morph and the Crystal court. The Crystal court plays normally, but the Morph court has an added gimmick. When a player performs a chance shot, and if the chance shot does not get volleyed, the type of floor on the opponents court changes to various patterns from other courts in this game, which affect ball velocity and bounce. A unique floor, a black hole pattern, erratically alters the direction of the ball bounce into one extreme direction. Only one part of the court can get altered: the player must perform a chance shot to change the pattern in the opponents court and the player must perform a chance shot to remove the court's current pattern.
 Names in Other Languages
- As opposed to its reference to Super Mario Galaxy, Galaxy Arena is the only accessible place in the Mario series where the player is able to view both the Comet Observatory and the Gateway Galaxy's starting planet visible at the same time in close proximity. Unlike in Super Mario Galaxy, the player cannot visibly see both the observatory and the planet at the same time.