- Bowser = When you enter the battlefield, make sure you have a Koopa Shell. Then slide in and you will slide into Bowser, which kills him instantly.
- Luigi = When you enter the level, go to the fifth house. Enter the door to see that it's Mario's house. Luigi is in the kitchen. Talk to him and he'll join.
- Wario Bros. = Enter the tower with 1,000,000 coins. Defeat the Wario Bros. and the coins will fall out of your pocket. The Wario Bros. will see them and ask you if they can join. Say yes and they do.
- Peach and Me (Toad) = Beat King Kaliente in Burning Fortress as Mini Mario. When you do, you will run into the room and fall through a Mini Mario hole. Mario will continue running and see Peach and Toad. Use a Mega Mushroom at that point and they will agree to help (because they can now get out).
- Yoshi = When you get to Larry he will be riding on a Yoshi. To get this Yoshi you must defeat Larry.
- Birdo = Beat the Wiggler without making him angry.
- World 1-2 = When you get to the checkpoint, use a propeller suit and spin up. You will enter a new place with the flagpole right in front of you.
- Wiggler = Get to him as a boss. While he's asleep, jump on him. Then ground pound his head. A baby Wiggler will appear. Jump on him and you will automatically beat the level, as well as being able to ride the Wiggler until you die. The Wiggler can dash really fast, and when dashing is invincible.
- Yoshi = When you get to Larry, become Mini Mario. Jump on Larry and he dies. You can now ride the Yoshi!!! He can do the same thing as in NSMBW.