Frank Welker

as Scooby-Doo / Fred Jones (voice)

Matthew Lillard

as Shaggy Rogers (voice)

Grey DeLisle

as Daphne Blake (voice)

Mindy Cohn

as Velma Dinkley (voice)

Mark Hamill

as Zip Elvin (voice)

Diedrich Bader

as H.A.M. (voice)

Malcolm McDowell

as Sly Baron (voice)

Fred Tatasciore

as Hudson Baron / Alien (voice)

Jennifer Hale

as Shannon Lucas / Ridley / Launch Manager (voice)

Jeff Bennett

as Colt Steelcase (voice)

Kevin Michael Richardson

as Uvinous "U-Boat" Botango / Drake (voice)

Eric Bauza

as Clark Sporkman (voice)