Mario Kart DS includes a wide variety of characters from the Mario universe. There are twelve characters to choose from, but four of these must be unlocked before you can select them. Shy Guy is another playable character, but only through DS Download Play.
The characters are grouped by their weight - Light, Medium and Heavy. Light drivers have great acceleration and handling but poor top speed. Heavy drivers have great top speed but poor handling and acceleration. Medium drivers are pretty good at speed, handling and acceleration.
NOTE: The performance of the kart also has a big influence on your character's performance, so make sure you choose a good combination of kart and driver.
- Yoshi: Yoshi is everyone's favorite green dinosaur. In the past, Yoshi started as a mount for Mario, though now Yoshi has been given his own series. Yoshi is a light racer with great acceleration and handling.
- Peach: The resident damsel in distress of the Mushroom Kingdom, and love interest to Mario. Countless Mario games focus on Bowser kidnapping her and Mario rescuing her. She's a very light character with good acceleration and great drifting.
- Toad: Toad is an assistant to Princess Peach. He tries to help Peach but fails and then gives Mario helpful advice. Toad is a light character and has great acceleration.
- Dry Bones: Skeletal foe in many a game, this racer is very light, most likely due to a lack of flesh. Handles great and a popular power sliding character. Note: Dry Bones must be unlocked before you can choose it.
- Shy Guy: Shy Guy is a standard enemy from the Mario universe. In Mario Kart DS, he becomes playable to those who don't have their own Game Card and are using the single-card DS Download Play feature. Each player that doesn't have a Game Card will get a different color Shy Guy. He cannot be selected in any single-player or online game otherwise without an Action Replay.
- Mario: The hero of the Mushroom Kingdom, and the main protagonist of the Mario series. He has participated in numerous genres from tennis to golf. Mario is a balanced racer.
- Luigi: The not so famous brother of Mario. He usually tags along with Mario as more of a sidekick then an equal. Like Mario, Luigi is a balanced racer.
- Waluigi: His relationship with the Mario Bros. is as of yet unknown, but he is considered by many (if not all) to be Luigi's version of Wario as compared to Mario. Most of his cars are fast with decent handling. Note: Waluigi must be unlocked before you can choose him.
- Daisy: The "Damsel in Distress" in Super Mario Land, and love interest to Luigi. Daisy is another princess from another kingdom. Some believe, like Waluigi, she is Luigi's version of Peach. She's very light, quick, and an excellent drifter. Note: Daisy must be unlocked before you can choose her.
- Donkey Kong (DK): He's the monkey. Donkey Kong is a big ape who was once rivals with Mario at the start but is now stars in more of his own games separate from Mario. He's a heavy racer who can knock you off the track if given the chance.
- Bowser: Bowser is the classic villain and the main antagonist of the Mario games who repeatedly plots to kidnap Princess Peach. Fortunately, his plans are always foiled by Mario and Luigi. He's a heavy racer who can knock you off the track if given half a chance.
- Wario: Childhood friend and arch-rival of Mario, he was off cast as the bad guy, ultimately leading to his life of crime. He's a balanced/heavy player with lots of speed and handling, and less of an emphasis on items.
- R.O.B.: R.O.B. stands for "Robotic Operating Buddy". He was once an actual piece of hardware that Nintendo created to compliment the original Nintendo Entertainment System (NES). R.O.B. is a fairly heavy racer. Note: R.O.B. must be unlocked before you can choose him.