Brianne Siddall

Thunder / Dylan (voice)

Shanelle Gray

Maggie (voice)

Robin Atkin Downes

Jack / Carlo (voice)

Doug Stone

Mr. Lawrence (voice)

Grant George

Daniel (voice)

Joey Camen

Chihuahua (voice)

Elisa Gabrielli

Carla (voice)

Cinda Adams

Nurse Baxter (voice)

Sage Sommer

Izzy (voice)

Kyle Hebert

Mark Matthews (voice)

Bill Parks

Mike Matthews (voice)

Ella Rouhier

Hospital children (voice)

Noah Ray Strauss

Hospital children (voice)

Isabella Tatone

Hospital children (voice)

Keegan Thomas

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)