Is there a Bakugan season 3?

Yes, there is a third season of Bakugan. It is titled Bakugan: Gundalian Invaders and aired from March 23, 2010, to January 22, 2011. The season introduces a new group of Bakugan called the Gundalians, who come from a planet called Gundalia and are at war with the Bakugan of Earth. The Brawlers must team up with a group of Gundalian Bakugan to stop the Gundalian Invaders and save both Earth and Gundalia.