M&M's Beach Party is a game based on the M&M's chocolate brand with a beach party theme. Players select an M&M's character based on five colors (red, orange, green, yellow or blue) and then get to explore a beach environment that offers six mini-games for up to four players. Open spots can be filled in with computer-controlled players, so the game can also be played alone. The mini-games are Kayak Racing, Mr. Runch Slam, Ring Toss, Skee Ball, Target Shooting and Volleyball. They are however locked at the start and only become available after collecting a number of items such as shells. Additional game variants, such as faster moving lily pads in the Mr. Runch Slam game, are also unlocked in the same way. Each game shows some instructions before it is played.

In Ring Toss the characters stand on a pier and need to throw ring discs onto buoys in the ocean. The A button is used to switch between angling and strafing and the B button is used to pull back and throw. Skee Ball has similar controls. First the character needs to move to line up the shot and then the B button is used to swing. Volleyball is played from a side-view with up to two players per team serving, receiving, passing and smashing the ball. Timing is important so as not to drop the ball. Target Shooting plays like a shooting gallery game where players move the cross-hairs against a static background to sling paint at characters and objects. The Wii Remote needs to be shaken to refill the can of paint. Mr. Runch Slam shows a chocolate pond with floating M&M's lily pads. The player has to time launching an object by smashing a hammer to hit the pads to score. It is also possible to rotate to change the angle. Kayak Racing is a fast race in the ocean with kayaks to reach the finish line first. Games have multiple difficulty levels.