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)