Season 18 was officially announced on March 1st, 2013 after the Bali reunion. Sandros, Kirin and Tucker confirmed their return to the series along with newcomer Adrian. Casting for the season began June 22nd, 2013 through the game forum with the cast announcement on July 14th. This season saw the first full cast of new players since Congo with the roster expanded to eighteen. When it came to choose the cast, Production introduced a third tribe (La Araña) at the last minute due to balance out stronger players.
Other twists up for consideration were East Coast vs. West Coast and tribes based on their status in the Educational system (Middle School, High School, College, University etc.) a second U.S. vs. The World originally used in Congo was also up for consideration but was rejected and later used in Russia. Alumni of the series were invited to watch the game and vote in weekly polls and discuss the game in real-time. Seven former players were selected as Prediction Writers who would have access to castaway journals whilst the Alumni would have exclusive access to tribe forums.
iSurv1vor is ran on the free message board service Proboards which involved a drastic change in the way the forum is designed in April 2013. Mexico will be the first season to be played under the new style. The Production Team have confirmed that this season, those exclusive to the alumni group will have access to confessionals.
Tribal Council Idol
Similar to that of the Hidden Immunity Idol in Congo, the castaways were informed that their iS Points (pesos) would be used to take part in a Silent Auction at the start of their Tribal Council. When a player casts their vote privately, they will also bid all or a portion of the points they've earned so far in the competition. If they are successful, the Idol immediately negates any/all votes cast against that person. The Idol is then returned to the Host and will appear at subsequent Tribal Councils until the Final Five players. Buying the Idol to play on another person is not permitted.
As is routine with Online Reality Games, certain players have competed with/against the same people. This season, twelve of the castaways were informed they would be playing against somebody they know and they are under no obligation to work together, similar to Bermuda.