Instructions
Unlock the first three hidden characters. To earn Baby Daisy, earn a "One Star" ranking or higher in all of the 50cc Cups. You'll receive Baby Luigi after unlocking eight expert staff ghosts, which requires beating eight regular staff ghosts by seven seconds or more. Unlock the tiny Birdo by racing in all 16 courses in time trial mode.
Earn more hidden racers through your achievements. Open Bowser Jr. by getting a "One Star" ranking or better on the 100cc Retro Cups. Medal in all 50cc cups to unlock Diddy Kong, and earn Dry Bones by beating the Leaf Cup.
Open Dry Bowser by getting a "One Star" ranking in each 150cc WIi Cup. You'll earn Funky Kong after earning four expert ghosts, and King Boo will become available immediately after beating the 50cc Star Cup. Open Rosalina by getting "One Star" or better in all of the 50cc Mirror Cups.
Earn the tiny Toadette by one of two methods: either compete in each of the 32 courses in Time Trial mode or play 1,000 Wi-Fi matches online. Unlock the Mii Outfit 1 character you've designed by winning the 100cc Special Cup and Mii Outfit 2 by unlocking all 32 expert ghosts, which is the toughest challenge in the game. Use the shortcut FAQs in Resources for help beating all the ghosts.