Samuel Blenkin
as Boy Kavalier
Babou Ceesay
as Kumi Morrow
Sydney Chandler
as Wendy
Alex Lawther
as Joe Hermit
Essie Davis
as Dame Sylvia
Adarsh Gourav
as Slightly
Timothy Olyphant
as Kirsh
Jonathan Ajayi
as Smee
Erana James
as Curly
Lily Newmark
as Nibs
Diêm Camille
as Siberian
Adrian Edmondson
as Atom Eins
David Rysdahl
as Arthur Sylvia
Moe Bar-El
as Benjamin Rashidi