Anne Suzuki
Masane Tsukayama
Katsuo Nakamura
Manami Konishi
Kiyoshi Kodama
Ikki Sawamura
Susumu Terajima
Anna Paquin
Alfred Molina
Patrick Stewart

Anne Suzuki as James Ray Steam (voice)
Masane Tsukayama as Dr. Eddie Steam (voice)
Katsuo Nakamura as Dr. Lloyd Steam (voice)
Manami Konishi as Scarlett O'Hara (voice)
Kiyoshi Kodama as Robert Stephenson (voice)
Ikki Sawamura as David (voice)
Susumu Terajima as Freddie (voice)
Anna Paquin as James Ray Steam (voice: English version)
Alfred Molina as Dr. Eddie Steam (voice: English version)
Patrick Stewart as Dr. Lloyd Steam (voice: English version)
Kari Wahlgren as Scarlett O'Hara (voice: English version)
Robin Atkin Downes as David (voice: English version)
David S. Lee as Jason (voice: English version)
Paula J. Newman as Emma (voice: English version)
Moira Quirk as Cliff, Tommy, Additional Voices (voice: English version)