Mario Kart World supports races with up to 24 drivers at once.
That total is one of the game’s clearest scale increases over earlier Mario Kart entries. The 24-driver field is twice the size of the previous series maximum cited in the game’s background information, creating a much busier race environment.
The larger field is particularly important in Knockout Tour, where a long route carries the racers through multiple parts of the game world. Drivers pass checkpoints, and the lowest-ranked racers are removed as the event continues.
A common mix-up is to count only human players. The 24-driver figure describes the full race field, which can include computer-controlled opponents. It does not mean that every race requires 24 people playing locally or online.