Brianne Siddall

Thunder / Dylan (voice)

Shanelle Gray

Maggie (voice)

Robin Atkin Downes

Jack / Carlo (voice)

Grant George

Daniel (voice)

Joey Camen

Chihuahua (voice)

Elisa Gabrielli

Carla (voice)

Cinda Adams

Nurse Baxter (voice)

Kyle Hebert

Mark Matthews (voice)

Bill Parks

Mike Matthews (voice)

Ella Rouhier

Hospital children (voice)

Jim Ward

Reggie (voice)

Susanne Blakeslee

Audrey (voice)

Roxanne Reese

Lasondra (voice)

Joe Ochman

Mr. Eames (voice)

Grey DeLisle

Mrs. Eames (voice)

Lani Minella

Old Lady (voice)

Frank Welker

Cat sounds (archive footage; uncredited)