Play Stadium 3 Codes -

Oldboys team:
Select "Homerun Race" mode, then choose "Single Play". Then, press X, Circle, Triangle, Square on controller two at the team selection screen. The Oldboys will now be selectable.

Oldboys team in Team Edit mode:
Press X, Circle, Triangle, Square on controller two at the uniform selection screen. The Oldboys will now be selectable.

Beach stadium:
Select "Homerun Race" mode, then press X, Circle, Triangle, Square on controller two at the stadium selection screen.

Sea stadium:
Select "Homerun Race" mode, then press Square, Triangle, Circle, X on controller two at the stadium selection screen.

Sky tower stadium:
Select "Homerun Race" mode, then press X(2), Circle, Up, Circle, Down, Triangle, Square on controller two at the stadium selection screen.