Grey DeLisle as Daphne Blake (voice)

Stephen Stanton as Peanut Vendor (voice)

Kari Wahlgren as Female Peasent (voice)

Frank Welker as Scooby-Doo / Fred Jones / Monster (voice)

Kate Micucci as Velma Dinkley / Sandi (voice)

Matthew Lillard as Shaggy Rogers (voice)

Nick Frost as Merlin (voice)

Greg Ellis as Herald / Herman Ellinger / British Passenger (voice)

Jason Isaacs as King Arthur Pendragon (voice)

Spike Brandt as Mr. HB (voice)

Trevor Devall as Man Cat (voice)

Fred Tatasciore as Black Knight (voice)

Ted Barton as Mayor Saunders / Sir Lancelot (voice)