If you're watching the One Piece anime.
I wrote down where each movie is placed and between what episodes you should watch them.
It took me ages.
One Piece: The Movie
Clockwork Island Adventure
Chopper's Kingdom on the Island of Strange Animals
Dead End Adventure
Curse Of The Sacred Sword
Baron Omatsuri and the Secret Island
The Giant Mechanical Soldier of Karakuri Castle
Ep 426-429 (Then One Piece Film: Strong World)
Ep 430- (Ongoing)
My friend dared me to put this here. I'll put it in below.