The battle system in Pokémon Colosseum is a turn-based, strategic affair that heavily emphasizes Double Battles. In a Double Battle, each trainer sends out two Pokémon to fight simultaneously. This means that moves targeting a single opponent can hit either of the opponent's Pokémon, and moves that affect all Pokémon on the field will impact both of yours and both of theirs. Understanding positioning and move selection is paramount.
Each Pokémon has a set of four moves, each with its own Power, Accuracy, and PP (Power Points). Moves can also have secondary effects, such as causing status conditions (like Paralysis, Sleep, or Poison) or raising/lowering stats. The order of turns is determined by each Pokémon's Speed stat. A Pokémon with higher Speed will typically attack before a Pokémon with lower Speed. Type matchups are also critical; certain types are strong against others, dealing double damage, while others are weak, dealing half damage. Mastering these fundamentals, including move selection, turn order, and type effectiveness, is key to winning battles.