Ferdia Walsh-Peelo

as Conor "Cosmo" Lawlor

Lucy Boynton

as Raphina

Jack Reynor

as Brendan Lawlor

Ben Carolan

as Darren

Mark McKenna

as Eamon

Kelly Thornton

as Ann Lawlor

Maria Doyle Kennedy

as Penny Lawlor

Aidan Gillen

as Robert Lawlor

Ian Kenny

as Barry

Percy Chamburuka

as Ngig

Connor Hamilton

as Larry

Karl Rice

as Garry

Don Wycherley

as Brother Baxter

Des Keogh

as Brother Barnabas

Kian Murphy

as Mick Mahon

Dolores Mullally

as Dinner Lady

Marcella Plunkett

as Eamon's Mum

Vera Nwabuwe

as Ngig's Mum

Tony Doyle

as Wayne

Keith McErlean

as Barry's Dad

Art Campion

as Evan

Lydia McGuinness

as Mrs. Dunne

Kyle Bradley Donaldson

as Fifth Former

Paul Gibbons

as Exam Supervisor

Eva-Jane Gaffney

as Jacinta

Paul Roe

as Surveyor

Pádraig J. Dunne

as Surveyor