Castaway: Island of the Idols

 is the fifteenth season of Castaway and was produced on September 5, 2021.

The season borrowed elements from the CBS reality television competition Survivor. Hosted by Robert, the game consisted of seventeen returning competitors and the third season to feature a cast consisting entirely of returning competitors following Castaway: Cambodia and Castaway: Redemption Island.

The two tribes, Lairo and Vokai were named after the Fijian words for "land crab", and "forest gecko" respectively. When fifteen competitors remained a third tribe, Boto, named after the Fijian word for "frog" was created. When ten competitors remained the tribes merged to the Agimat tribe, named by John M. after the Filipino word for Amulet. Yonatan won the season over Santi and Carson in a 5-2-0 vote.

The season introduces its namesake, Island of the Idols where players are given one lesson - risk - for an opportunity to earn or burn an advantage at the cost of losing their vote at Tribal Council. Burn the Urn, an unused twist from China and Micronesia returned alongside a new twist, the Fire Idol, that when played burns all votes against the player and are not read at Tribal Council. The Final Four elimination challenge made their fifth appearance.

Development and Casting
The season introduces "Island of the Idols" a similar twist to Exile Island where visitors to the Island of the Idols would be able to find different forms of advantages based on the lesson that the visitor(s) would face as a direct result. Visitors to the Island can choose to search at the cost of losing their vote at the upcoming Tribal Council, or not take anything, burn an advantage, and return to camp. In the first round the player not selected to join a tribe would be exiled to the Island of the Idols, and subsequent visitors would be determined by the previous inhabitant, if the previous inhabitant was voted out, the winner of Immunity (whether tribal or individual) would choose who attends. Unlike the parent series that featured two winners mentoring the visitor each episode, Robert scrapped the notion of having mentors due to the potential of having returning players already compete against the mentor in other seasons which would create a potential conflict of interest.

Originally planned to be all new players and was due to go into production on August 29, the decision was scrapped for a second back-to-back All-Star run concluding Castaway. When opening applications, Robert stated "if [returning players] want a chance to prove [their] worth before Battle Royale, now is the time"

Castaways
Due to an uneven cast size, the opening dilemma gave Lewis and Missy captaincy of Lairo and Vokai respectively. The player not selected, Bryan, was sent to the Island of the Idols and would join the losing tribe (Lairo) after the first Tribal Council.