Players can choose between sending out their Codemon for battle within a Codebox or choosing an opposing Codemon to battle, which does not require a Codebox. When challenging an opponent to a battle, Codemon can be up to two levels lower than the initial Codemon.
Prior to battle, players may choose a single spell to use on their Codemon for the battle in order to boost their powers. They may also choose to use a Healing Potion if their Codemon is injured and does not have full health points.
Battles move in a specific order. Spells are immediately used on a Codemon when the battle takes place. The effectiveness for both Codemon is displayed as well. After this, the actual battle commences and the Codemon begin to actually fight.
The amount of battles won and lost are recorded on a player's profile.
There are four achievements that have to do with battling:
- Who are you calling small? (win a battle against a Codemon two levels higher)
- Bronze Battler (participate in 100 battles)
- Silver Battler (participate in 1,000 battles)
- Gold Battler (participate in 10,000 battles)