The Final Two are the two contestants still remaining on the last day of the game, who must plead their cases to the Jury at the Final Tribal Council for the title of Sole Survivor. The Final Two was standard practice for the first five seasons, before being alternated with a Final Three starting from All-Stars.
All 16-person seasons (with the exception of Caicos Islands) have featured a Final Two as standard, due to the comparatively small size of the cast. Recent seasons though have featured an increase in cast sizes, and therefore the Final Two format has become less common. Bhutan saw the return of the Final Two, having been absent for six seasons since Jan Mayen. It has since become more regular again, appearing in both Kiribati and El Salvador.
18-person seasons are typically more likely to feature Final Threes, especially if there is a merge at twelve. However Occultus Island, Reclamation, and Puerto Rico have been exceptions to this, Occultus Island and Reclamation featured merges at eleven, while Puerto Rico featured a merge at twelve (although jury didn't start until eleven). Kiribati also featured a Final Two with an 18-person cast, but it had an even smaller Jury of Seven. Only one 20-person season has featured a Final Two so far, with that being Canary Islands.