One Piece doesn't have the ordering problem other franchises do: it's one continuous series running since 1999. Its problem is different: volume (over 1100 episodes) and filler scattered along the way. The right strategy isn't "what to watch first" — it's "what to skip".
- TV · 1100+ ep · 1999–ongoing
Watch in air order, start to finish, skipping the episodes flagged as filler in the list. Filler arcs never affect the main story.
The movies
15 movies · OptionalOptionalNo movie is required to follow the series. They're side stories made as extras — fun if you want more, safely ignorable if you're speedrunning.