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.
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.