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