Finn is currently 16 as confirmed in the season 6 finale "The Comet '' and the early season 8 episode "Wheels ''. At the beginning of the series, Finn was a 12 - year - old boy who is supposedly the only known human in the Land of Ooo. During the episode "Mystery Train '', Finn turned 13; it has been stated that the episode first airing date (March 14) is Finn 's birthday. After season 3 ended, Pendleton Ward stated in an interview that Finn was 14. Finn was 15 years old in the second half of Season 5, according to Adam Muto. In the Season 6 finale, "The Comet '', Finn reveals that he has reached 16 years of age. This means that unlike in many other cartoons where characters stay the same age or age through time skips, in Adventure Time time passes regularly.
how old is finn in adventure time season 8
16 16