One Piece season 1

The first season of the One Piece anime series aired on Fuji Television from October 20, 1999, through March 7, 2001, totaling 61 episodes. Produced by Toei Animation and directed by Kounosuke Uda, it adapts the first twelve volumes of the manga by Eiichiro Oda. The first season depicts the exploits of the pirate captain Monkey D. "Straw Hat" Luffy as he gathers his crew at the East Blue and prepares to head to the Grand Line, all while defeating local pirates in their path as they gain infamy. The last 8 episodes, set on Warship Island, are the first anime-original filler material in the series.

In 2004, 4Kids Entertainment licensed the series for a heavily edited English dubbed broadcast. 4Kids edited the episodes for content, merged one episode and left out 18 episodes, thus reducing the season's episode count to a total of 53 episodes. The series made its U.S. premiere on September 18, 2004, on Fox as part of its FoxBox TV programming block, lasting until July 30, 2005. Funimation Entertainment later licensed the series and released the first season in four unedited and uncut, bilingual-language compilations; the first was released on May 27, 2008, and the last was released on March 31, 2009.

The season uses four pieces of theme music: two opening themes and two ending themes. The first opening theme is the award-winning title "We Are!" (ウィーアー!, Wī Ā!), performed by Hiroshi Kitadani in Japanese and Vic Mignogna in English (Funimation dub; Russell Velazquez initially performed the English version for the 4Kids dub before replacing it with the "Pirate Rap") for the first 47 episodes. The second opening, which was used for the rest of the season, is "Believe" by Folder5 in Japanese and Meredith McCoy in English. The first ending theme, titled "Memories" for the first 30 episodes, and was performed by Maki Otsuki in Japanese and Brina Palencia in English, who also performed the second ending theme song, titled "Run! Run! Run!" in Japanese, for the rest of the season. Caitlin Glass performed the English version of the second ending theme. 4Kids used original music in their adaptation, while Funimation opted for English-language versions of the theme music pieces.