Castaway: Battle Royale

 is the sixteenth season of Castaway and was produced on October 24, 2021.

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

The two tribes, Dakal and Sele were named after the Fijian words for "gun" and "to cut", respectively. When eighteen competitors remained, Sindri and Tracy as representatives for their tribes were given a dilemma, swapping the tribes swapped into two tribes of nine as opposed to three tribes of six. When twelve competitors remained, the tribes merged to the I-Tokani tribe, named by Alejandro which is the Fijian word for Amigo. Bethaney won the season over Ganjo in a 5-4 vote.

The season introduced Scorched Earth, similar to the twist used in Island of the Idols where visitors could compete in a game to earn an advantage of their choice from a pre-determined list at the cost of losing their vote if unsuccessful. During the pre-merge portion of the competition, Tribal Council included two voting urns which the castaways could place their vote into, culminating in two eliminations per round. The Final Four elimination challenge made its sixth appearance with two competitors being eliminated as opposed to one, culminating in a final two facing a jury of nine.

Development and Casting
The sixteenth season of Castaway was confirmed soon after the finale of Castaway: Blood vs Water as the second All-Star season following Castaway: Island of the Idols. The season introduced "Scorched Earth", upon arrival the contestant must sacrifice their vote to compete in a challenge, if successful the contestant will earn their vote alongside an advantage of their choice from a pre-determined list. A variation on Tribal Council was introduced this season based on a suggestion by Burcham, the winner of Castaway: One World who later appeared on Castaway: Blood vs Water. At Tribal Council, castaways will vote in one of two Urns ("Fire" and "Water") with votes being read from both Urns culminating in two castaways being eliminated. Any Hidden Immunity Idol played would protect the holder from both Urns. Any votes cast for an eliminated castaway in the second Urn will not be read. If all castaways place a vote into one Urn, the two players with the highest number of votes will be eliminated. The season uses the "Game Changers" rules at Tribal Council, whereby if a tie occurs an immediate open forum is called to determine a unanimous decision, failure to reach a decision culminates in those in the tie becoming immune, and all eligible contestants participate in a rock draw.

Casting for the season began after the finale of Castaway: Island of the Idols with Robert approaching a shortlist of 100 former castaways with instructions to complete. On October 1st, those who had submitted their requested information were shortlisted with the final cast being determined from that shortened list. Successful applicants were notified of their casting over the course of several days starting on October 17th. The season features the largest cast in Castaway with twenty-six due in part to Robert wanting to make "the last chapter of [this] Castaway the biggest and boldest".

During the fifth episode "Yes", Sindri and Tracy as representatives for Dakal and Sele respectively were given a dilemma to an expected tribe swap - both options had their own advantage and disadvantage. If a tribe swap into two tribes of nine occurred, immunity challenges would be easier to win but the double urn twist would remain in play. If a tribe expansion into three tribes occurred, immunity challenges would be more difficult to win as only one tribe would secure immunity each round and the two losing tribes would vote out a castaway each. Sindri and Tracy retained the two tribes, though it was revealed that the schoolyard pick'em would end prematurely with the six not selected forming the Yara tribe.

Challenges for the season were based on Robert's favourites to host from across the series that previous competitors had a troublesome relationship with.