Nintendo has revealed new features for Mario Tennis Open, which is scheduled for release on May 25th, 2012.

Online Play: Players can communicate with each over over Wireless Internet connection, and play Tennis Tourney’s. There’s an “Open Tourney”, which allows players to raise their stats, see their monthly classes, and receive Medals for every beaten challenger.

Piranha Plant Party: In this Tourney, Piranha Plants will spit ink balls from the other side of the course. Players have to destroy these ink balls, before there’s to much of them, and at the same time, players have to play Tennis with each other.

StreetPass Features: Players can start a competition, using the 3DS’s StreetPass Functionality. They can challenge each other through StreetPass Tourney, or do Ring Shot together. You’ll just exchange CPU versions of the players you’ve met, and exchange your ‘winning streaks’. Players can also use StreetPass to show their Mii’s, which you can dress up with costumes, and accessoiries, which improve your stats. New items will be unlocked in the Item Shop.

Unlockable Characters: Players can unlock many known and less known Nintendo Characters, either by going through the game, or use special QR-Codes. Examples of Unlockable Characters are Luma, Baby Mario, and Dry Bowser.