From The Bakugan Wiki
A Bakugan Generation (Unofficial name) refers to a distinct era in the franchise's history. Currently there are three designated Generations of Bakugan:
- The First Generation, or Generation 1 - beginning at the start of the franchise and ending after the end of both Bakugan: Mechtanium Surge and Bakugan Armors
- The Second Generation, or Generation 2 - beginning at the start of Bakugan Battle Planet and ending after the end of Bakugan: Legends
- The Third Generation, or Generation 3 - beginning at the start of Bakugan, and continuing on currently.