Will Ferrell
Dr. Rick Marshall
Danny McBride
Will Stanton
Bobb'e J. Thompson
Tar Pits Kid
Sierra McCormick
Tar Pits Kid
Shannon Lemke
Tar Pits Kid
Steven Wash Jr.
Tar Pits Kid
Jon Kent Ethridge
Teenager
Sean Michael Guess
Elder Pakuni
Dennis McNicholas
Ice Cream Man
Chris Henchy
Stage Manager
Travis Samuel Clark
Sleestak
Todd Christian Hunter
Sleestak
Ana Alexander
Pakuni Woman
Pollyanna McIntosh
Pakuni Woman
Ania Spiering
Pakuni Woman
Paul Adelstein
Astronaut (voice)
Adam Behr
Library Skull (voice)
Daamen J. Krall
Library Skull (voice)
Leonard Nimoy
The Zarn (voice)
Michael Papajohn
Astronaut (uncredited)
Kiernan Shipka
Tar Pits Kid
Dylan Sprayberry
Tar Pits Kid (uncredited)
Zach Callison
Tar Pits Kid (uncredited)