One Piece Odyssey is a turn-based role-playing game in which players control Monkey D. Luffy and the Straw Hat Pirates. Every playable character has a unique ability in line with their powers, which are used for traversal, collecting items, and solving puzzles. After engaging an enemy in the field, the game transitions to the battle screen, where the characters' actions are controlled using menu commands. The combat system revolves around "Scramble Area Battles" system, where battles are divided into several areas.

Players can optimize the positions of party members between areas to counter opponents. In some battles a random element of the system titled "Dramatic Scene" places the player in inconvenient situations playing to the characters' personalities, such as Sanji being unable to attack because he is surrounded by women, and overcoming them nets greater rewards. As with other games in the genre, the party members earn experience points after battle and level up once enough points are accumulated.