One-piece is an item of clothing in the some video games. It can only be worn by female players. The male alternative to this is the denim jacket.
Several female duelists in Story Mode that are not central to the storyline wear the One-piece, including in Yu-Gi-Oh! 5D's World Championship 2011: Over the Nexus where the outfit is not available to the player.
In Yu-Gi-Oh! 5D's World Championship 2009: Stardust Accelerator, the One-piece is available from the start.
Reverse of Arcadia
In Yu-Gi-Oh! 5D's World Championship 2010: Reverse of Arcadia, the One-piece can be purchased from Chihiro.