Emma Roberts as Rex Simpson

Tom Hopper as Logan O'Leary

Poppy Liu as Nadine Cai

Gabrielle Union as Pam Proctor

Kuhoo Verma as Violet Marie Vislawski

Desi Lydic as Dr. Stacy Kellogg

Sebastián Yatra as Toddrick Spencer

Sam Robards as Rex's Dad (Calvin Simpson)

Dave Foley as Rudolph Bolton

Yasha Jackson as Grace Jackson

Andrew Call as Captain Jack Mancini

Josephine Huang as Miriam Osprey

Troy Iwata as Hector Kaneko

Caroline Concannon as Rex Simpson - 8 years old

John Ahlin as Gator Greg

Tómas Matos as Johnny

Fergie L. Philippe as Bingo

Alli Brown as Paris

Glo Tavarez as Kendra

Allegra Heart as Erin

Neal Davidson as Cold Water Dude

Natasha Warner as Rex's Mom (Tara Simpson)

Makia Martin as Condemned Mansion Tourist

Max Jenkins as Miles the Med Tech

Alyson Schacherer as Tourist Mom

Shirley Roeca as Dee Bellevue

Joshua Harto as Captain Elvis Popowski

Merritt Janson as Departing Ascan

Alexis Suarez as Flight Captain

Drew Powell as Drunk Customer (Lucas)

Eddie A. Bryant as Head of Security

Kevin Downes as Security Guard

Michael J. Massimino as Astronaut #1

Gideon Yu as Astronaut #2

Les Ware as Astronaut #3

Brennan Joseph Taylor as Sweaty Ascan

Kimberly Pauley as Guidance Counselor

Cooper Silverman as Beach Partygoer

Samira Sardella as Space Camp Girl #1

Ollie Gregorio as Space Camp Girl #2

Jaynalie Rios as Space Camp Girl #3

Wilder Garcia-Harto as Tourist Kid #1

August Garcia-Harto as Tourist Kid #2