Rainbow Road is the final course of the Special Cup. It is the most difficult course in the game. It is also one of the longest courses in the game. The only obstacles are some gaps in the road. It is a road in a rainbow-colored pattern over planet Earth in space and you disintegrate when you fall off the road. There is a cannon that looks like a golden balloon shaped as a star. Its staff ghost is Princess Rosalina.
- When a racer uses a Mushroom or Golden Mushroom, after the finish line right before the racer goes down the the top of the hill, the racer can fly down the track all the way to the first boost pad, which saves some time.
- When a racer enters the mid-section of the course, the part with the two large circles, the racer needs to stay close to the right side until after the racer passes the second circle, then quickly make a sharp right turn (depending what side you're riding on) riding very close the edge then right before the racer is about to run off the track, leaving enough time to actually use the mushroom before they fall off, use the mushroom to pass over a big gap, saving little, but some time.
Note: There are several videos on YouTube showing how to do these shortcuts.