How do you get masterballs in Pokemon platinum?

* Winning the Battle Frontier. The Battle Frontier is a post-game facility where players can battle against tough opponents and earn various prizes. One of the prizes that can be earned is the Master Ball.

* Buying them from the Underground Man in the Veilstone Department Store. The Underground Man sells various items, including Master Balls, for BP (Battle Points). BP can be earned by battling and winning in the Underground.

* Prize for completing the Sinnoh Pokédex.

* Using a cheat device.