Taylor Lautner

Sharkboy

Taylor Dooley

Lavagirl

Cayden Boyd

Max

David Arquette

Max's Dad

Kristin Davis

Max's Mom

Jacob Davich

Linus / Minus

Sasha Pieterse

Marissa / Ice Princess

George Lopez

Mr. Electricidad / Tobor / Ice Guardian

Rico Torres

Sharkboy's Dad

Marc Musso

Classroom Kid #1

Shane Graham

Classroom Kid #2

Racer Rodriguez

Sharkboy, Age 7

Rebel Rodriguez

Sharkboy, Age 5

Robert Rodriguez

Shark (voice) (uncredited)

Araceli González

Principal (uncredited)