[1] Contestants on the show are a combination of alumni from seasons of various reality televisions shows, including The Real World, Road Rules, Are You the One?, Big Brother, and Ex on the Beach, contestants who debuted directly on The Challenge, professional athletes, as well as other celebrities.
Prior to the twelfth season, Fresh Meat, contestants had only been from The Real World and Road Rules.
Since the 31st season, casting has expanded to feature alumni from several reality television shows, including Big Brother, Ex on the Beach, and Geordie Shore.
Contestants are regularly brought back for multiple seasons and use their veteran status along with relationships with other returnees to their advantage.
[2] Camila Nakagawa debuted on the Spring Break Challenge and was on the winning team, and later became the only player to compete on the main series.