Jason Ian Drucker as Greg Heffley

Alicia Silverstone as Susan Heffley

Tom Everett Scott as Frank Heffley

Charlie Wright as Rodrick Heffley

Owen Asztalos as Rowley Jefferson

Wyatt Walters as Manny Heffley

Dylan Walters as Manny Heffley

Joshua Hoover as Mac Digby

Chris Coppola as Beardo

Kimberli Lincoln as Mrs. Beardo

Mira Silverman as Brandi Beardo

Carlos Guerrero as Luis

Danny Vinson as Hog Man

Stephen 'Big Steve' Dupree as Tall Farmer

Neva Howell as Farmer Lady

Ricky Muse as Butter Vendor

Taylor St. Clair as Carnie

Kurt Yue as Fake Dad

Jacinte Blankenship as Security Guard

Beth Keener as Reporter

Mimi Gould as Meemaw

Emma Wetzel as Country Fair Girl

Elijah Marcano as Corny's Host

Apollo GT as XBox Vendor / DXRacer Player

Alma Kent as Teen Bystander

Alexa Blair Robertson as Cute Girl #1

Courtney Lauren Cummings as Cute Girl #2

Robert Hendren as Motorcycle Cop

Sofia Bowers as Pigtails Girl

Jody Thompson as Uncle Gerald

Stephen Ruffin as Gamer

Anthony Ianitello as Diaper Hands Cosplayer

Nathaniel Dickson as Brandon Beardo

Jake Sterner as Brent Beardo

Bobby Akers as Gaming Expo Attendee (uncredited)

Lariah Alexandria as Corny Kid (uncredited)

Madison Alsobrook as Expo Kid (uncredited)

Cassidy Balkcom as Corny's Waitress (uncredited)

Taylor Barton as Fair Kid (uncredited)

Alicia Beshears as Fair Teen (uncredited)

Kimberly Blaurock as Professional Cosplayer (uncredited)

Joshua Booker as Gaming Expo Attendee (uncredited)

Maiya Boyd as Corny Heeley Kid (uncredited)

Michael Bunch as Laughing Corny's Waiter (uncredited)

Benton Burnett as Cowboy Family (uncredited)

Randy Burnett as Cowboy Family (uncredited)

Jamel Chambers as Expo Gamer Attendee (uncredited)

Jeremy Chesser as Corny Patron (uncredited)

Kristen Danielle as Expo Gamer (uncredited)

Aerielle Dodson as Goth County Fair Patron (uncredited)

Jacob Evans as Expo Kid (uncredited)

Juan Gaspard as Festival Vendor (uncredited)

James Gill as Steampunk Giant (uncredited)

Ben Hammock as Fair Employee (uncredited)

Simone Kiffany Jenkins as Passenger (uncredited)

Kenneth Jones as Mechanic (uncredited)

Tegan Jones as Party Guest (uncredited)

Jay D. Kacho as Man Splashed by the Pool (uncredited)

Jeff Kinney as Man at Player Expo (uncredited)

Tylon Larry as Fair Kid (uncredited)

Shane Donovan Lewis as Corny's Kid (uncredited)

John Merical as Driver (uncredited)

Davis Pak as Boy (voice) (uncredited)

Anthony Vance Pierce as Adult Fairgoer (uncredited)

Candy Rachor as Corny Patron (uncredited)

Jonathan Rush as Expo Gamer Attendee (uncredited)