Dakota Fanning as Mina / Lucy

Georgina Campbell as Ciara

Olwen Fouéré as Madeline

Oliver Finnegan as Daniel

Alistair Brammer as John

John Lynch as Kilmartin

Siobhan Hewlett as Mina's Mother

Hannah Dargan as Young Mina

Emily Dargan as Young Lucy

Joel Figueroa as Darwin (voice)

Thabile Michelle Hlongwane as Newscaster

Anthony Morris as Burke

Shane O'Regan as Collin

Jim Tighe as Bus Driver

Zarima McDermott as University Student

Morgan Bailey-Rocks as Younger Boy

Christian Bailey-Rocks as Older Brother

Éabha Connolly as Little Girl

Hannah Howland as Chloe

Kya Brame as Georgia

Ffion Haf as Daria

Shannon Antonia as Tanya

Kofi De Graft Jordan as Bobby

Charles Camrose as Conor

Charlie Mann as Romeo

Jacob Greenway as Jordan

Andrea Bechis as Dom

Cara Steele as Millie

Seán T. Ó Meallaigh as Watcher (voice)

Diarmuid de Faoite as Watcher 1

Ann Marie Horan as Watcher 2

Niamh McHenry as Woman in Shop (uncredited)