Chloë Grace Moretz as Maude Garrett

Nick Robinson as Stu Beckell

Beulah Koale as Anton Williams

Taylor John Smith as Walter Quaid

Callan Mulvey as John Reeves

Benedict Wall as Tommy Dorn

Byron Coll as Terrence Taggart

Joe Witkowski as Bradley Finch

Liam Legge as Baby

Asher Bridle as Baby

Ryan Cooper as WWII Cartoon Narrator (voice) (uncredited)