Daryl Sabara as Rex Salazar (voice)

Yuri Lowenthal as Ben Tennyson/Upgrade (voice)

Wally Kurth as Agent Six (voice)

Grey DeLisle as Dr. Holiday (voice)

John DiMaggio as Bobo Haha/Rath (voice)

J.K. Simmons as White Knight (voice)

Michael Emerson as Alpha Nanite (voice)

Jennifer Hale as Black Knight (voice)

Freddy Rodríguez as Ceaser Salazar (voice)

Dee Bradley Baker as Humungosaur/Diamondhead/Lodestar/Big Chill/Upchuck (voice)

David Kaye as Shocksquatch (voice)