There are nine bonus characters to unlock in Mario Kart 7 for the Nintendo 3DS.
Here are the bonus characters you can unlock, and what you need to do to unlock them.
Daisy – Get first place in the Mushroom Cup on 150cc difficulty
Honey Queen – Get first place in the Banana Cup on 150cc difficulty
Lakitu – Get first place in the Lightning Cup on 150cc difficulty
Metal Mario – Get first place in the Special Cup on 150cc difficulty
Mii – Win all cups in any of the CC races
Rosalina – Get first place in the Star Cup on 150cc difficulty
Shy Guy – Get first place in the Shell Cup on 150cc difficulty
Wario – Get first place in the Flower Cup on 150cc difficulty
Wiggler – Get first place in the Leaf Cup on 150cc difficulty