How can I unlock all the characters in Mario Kart Tour?

To unlock all the characters in "Mario Kart Tour," one must actively participate in the game by participating in various races, completing challenges, and earning rewards from the Pipe, which is the game's gacha-like mechanic for unlocking new drivers, karts, and gliders. Players receive Rubies as they progress, which they can use to fire the Pipe for a chance to get new characters. Additionally, players can accumulate Grand Stars to unlock Tour Gifts that may contain new characters. As the game introduces new tours every two weeks, featuring new and returning characters, keeping up with these events is crucial. Lastly, some characters might only be available through in-app purchases or special promotional events, so staying engaged with the game's updates and offers can help in collecting all the characters.