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
Tiger Darrow
Classroom Kid #3
Racer Rodriguez
Sharkboy, Age 7
Rebel Rodriguez
Sharkboy, Age 5
Rocket Rodriguez
Lug
Robert Rodriguez
Shark (voice) (uncredited)
Araceli González
Principal (uncredited)
Peyton Hayslip
Teacher (uncredited)
Tania Haddad
Classroom Kid (uncredited)