To get to the Battle Frontier, you must defeat the Elite Four with Pokemon only with your I.D. number. After you defeat them, you will get a ticket from your father to get to the Battle Frontier. The Battle Frontier is another region with fourteen more badges to collect. Additionally, there are seven gyms in the Battle Frontier. The seven gyms are the Battle Tube, Battle Dome, Battle Factory, Battle Arena, Battle Palace, Battle Pyramid, and Battle Tower. Each gym has two badges to collect.