Arena is a unique Group game mode in Super Smash Flash 2 where a variety of unique minigames can be played using the Sandbag. The arenas being played on depends on the game being played but all consists of enclosed stages where it is not possible to KO someone due to the hard, imprentrable walls. It can be considered the multiplayer equivalent of Stadium. It was first announced on the Super Smash Flash 2 Beta Direct on January 25, 2015. The total number of games that will be available in Arena is unknown.
Arena is also available to play in online matches, where it is called Online Arena.
- Sandbag Soccer: Players have to knock Sandbag into their opponent's goal.
- Sandbag Basketball: Players have to launch Sandbag into their opponent's hoop net.