Slateport City/Places of Interest/Battle Tent

The Battle Tent can only be found in. It is one of the three Battle Tents found in Emerald. Entrants pick out three Pokémon from a list of 6 random rentals, all at level 30. Then, three Trainers battle, having a chance after each battle to possibly trade a Pokémon for one from the person that was just defeated.