The Three-Tribe Format is a major tribe division twist that increases the number of competing tribes during the pre-merge phase of the game from two to three. It is the single most recurring twist in Suitman's Survivor besides Hidden Immunity Idols, which feature in every season. It first appeared as a one-off twist for the all-returnee cast in Survivor: All-Stars, and did not appear again for ten seasons, when it returned in the all-newbie Cursed Hand. Since then it has become a more frequently recurring twist, especially in recent seasons, having now appeared a total of twelve times as of Survivor: Canary Islands.
The idea behind the three-tribe format is to change up how the numbers work in the game. Whereas the basic two tribes can give one tribe an automatic numbers advantage, the extra tribe switches this up so that one specific tribe would have to get others on their side for a majority. Seasons with this format most commonly feature 18 castaways due to it being the most ideal number to still maintain equal numbers distribution, however this was increased to 21 for the all-star Survivor: Polynesia season. The downside to the three-tribe format means that the small numbers cause one tribe to fail more dramatically at the immunity challenges and lose a large chunk of their tribe. To stem this, a tribe switch usually dismantles one of the tribes, leaving the remaining two with mixed numbers from all three tribes. There have been variations to this. Survivor: Conqueror's Crusade featured two tribe switches which dismantled the Batelov tribe in the first swap, and then re-setablished it after the second, which ran until the merge. Kiribati featured multiple switched due to the Roulette Wheel twist, which changed the format between two and three tribes with each swap. Unfinished Business introduced the Solenzo tribe after a tribe swap, introducing the three-tribe format into the game after previously starting with the basic two tribes, and Canary Islands introduced the Graciosa tribe after a tribe swap, also introducing the three-tribe format into the game after previously starting with the two basic tribes.
The sixth season, Survivor: All-Stars, was the first to feature the three-tribe format. It was brought in to complement the significance of it being an all-returnee cast for the first time.
Charleroi Leuven Seraing
The sixteenth season, Survivor: Cursed Hand, was the second to feature the three-tribe format. It divided the tribes of all-new castaways based on their color level through the Color Level Hierarchy twist.
Chingola Lusaka Solwezi
The seventeenth season, Survivor: Reclamation, was the third to feature the three-tribe format. It passed off the standard returnees vs. newbies idea in favor of placing three of each across three tribes.
Alotau Madang Talasea
The twenty-second season, Survivor: New Zealand, was the fourth to feature the three-tribe format. It divided the tribes of all-returnee castaways based on their classification in the Failures vs. Finalists vs. Favorites twist.
Kaota Mamoe Takoto
The twenty-seventh season, Survivor: Kiribati, was the seventh to feature the three-tribe format. It divided the tribes of new and returning castaways based on their employment and aspirations through the Occupational Hazard twist.
Buariki Paelau Riaria
The thirtieth season, Survivor: Polynesia, was the eighth to feature the three-tribe format. It divided the tribes of all-returnee castaways based on their classification in the Strong vs. Social vs. Strategic twist.
Savave Tanrake Vaiaku
The thirty-second season, Survivor: Unfinished Business, was the ninth to feature the three-tribe format. It divided the tribes of all-returnee castaways into two tribes from the beginning, by random draw, but introduced a third tribe in a tribe switch.
Banfora Garango Solenzo
The thirty-third season, Survivor: Puerto Rico, was the tenth to feature the three-tribe format. It divided the tribes of new and returning castaways based on their classification in the Fans vs. Fools vs. Floaters twist.
Anasco Bayamon Corozal
The thirty-third season, Survivor: Ayia Thekla, was the eleventh to feature the three-tribe format. It gave three "legend" former castaways the opportunity to build their own tribes of new and returning players, in a twist known as Bloodlines.
Larnaca Nicosia Paphos
The thirty-eighth season, Survivor: Canary Islands, was the twlefth to feature the three-tribe format. It divided the cast castaways into two tribes, veterans against newbies, from the beginning, by random draw, but introduced a third tribe in a tribe switch.
Alegranza El Hierro Graciosa
Entitled vs. Earned
The thirty-ninth season, Survivor: Entitled vs. Earned, was the thirteenth to feature the three-tribe format. The full cast of twelve Entitled and twelve Earned castaways were divided by a random draw, courtesy of the Roulette Wheel.
Kapalai Malacca Redang