Mario & Sonic at the London 2012 Olympic Games is a collection of numerous events based on the Olympic Games. Mario & Sonic brings together the two titular characters and eighteen more from both franchises to participate in environments based on the official venues of the 2012 Summer Olympics in London. The characters are divided into four categories: all-around, speed, power, and skill. The same characters are playable as the previous game, with more focus being put on the events and gameplay.
Several Olympic events on the Wii, including soccer, badminton, and equestrian debut alongside improved versions of previously existing events such as athletics, aquatics, and table tennis. The Wii game introduces new "Dream Events", which are alternate versions of Olympic events taking place in locations from older games of the Mario and Sonic series. The Wii version also introduces new cooperative mechanics and a Party mode.