Is ONE PIECE episode 80 filler?
Canon No, episode 80 of ONE PIECE is canon.
#80
An Island without Doctors? Adventure in a Nameless Land!
医者のいない島？名も無き国の冒険！
Aired 9 Sept 2001
Mochibayo compiled this list from MyAnimeList's labels, because MyAnimeList's episode data is not reaching us at the moment.