How do I unlock all characters in Mario Kart Tour?

To unlock all characters in Mario Kart Tour, one needs to persistently play the game and collect Rubies, which can be used to fire the Pipe. The Pipe gives out random rewards, including new characters, karts, and gliders. By participating in tours, completing challenges, ranking up in races, and possibly purchasing in-game currency or earning it through promotions and login bonuses, players can accumulate the necessary Rubies to use the Pipe. Additionally, some characters may be unlocked by achieving high ranks in certain cups or as part of tour-specific gifts and rewards. Progressing through the game and taking advantage of event-specific features increases one's chances of unlocking all characters over time. It's important to note that since Mario Kart Tour is a free-to-start game with optional in-app purchases, having patience or choosing to spend money can both influence how quickly one completes their character collection.