Is ONE PIECE episode 11 filler?
Canon No, episode 11 of ONE PIECE is canon.
#11
Expose the Plot! Pirate Butler, Captain Kuro!
陰謀を暴け！海賊執事キャプテンクロ
Aired 26 Jan 2000
Mochibayo compiled this list from MyAnimeList's labels, because MyAnimeList's episode data is not reaching us at the moment.