Note: This game is also titled Super Mario Stadium Miracle Baseball.

Coin Derby mini-game
Successfully complete Challenge mode to unlock the Coin Derby mini-game.

Star Dash mini-game
Successfully complete all six mini-games on the Star difficulty setting to unlock the Star Dash mini-game.

Koopa Castle stadium
Successfully complete Challenge mode to unlock the Koopa Castle stadium.

Play as Baby Luigi
Successfully complete Challenge mode with Yoshi to unlock Baby Luigi.

Play as Bowser
Successfully complete Challenge mode on Special with any character to unlock Bowser.

Play as Dixie Kong
Successfully complete Challenge mode with Donkey Kong to unlock Dixie Kong.

Play as Hammer Bro
Successfully complete Challenge mode with Bowser to unlock Hammer Bro.

Play as Monty Mole
Successfully complete Challenge mode with Mario to unlock Monty Mole.

Play as Petey Piranha
Successfully complete Challenge mode with Wario to unlock Petey Piranha.

Play as Toadette
Successfully complete Challenge mode with Peach to unlock Toadette.