One year later, in the week of the Good Friday Agreement referendum, the gang prepare for their final school year and Erin and Orla's 18th birthday party. What does the future hold?
| Name | Type | Role | |
|---|---|---|---|
| Lisa McGee | Writer | ||
| Art Campion | Guest Star | Father Peter | |
| Donna Traynor | Guest Star | Donna Traynor | |
| Laurie Kynaston | Guest Star | Philip | |
| Kevin McAleer | Guest Star | Uncle Colm | |
| Clara Geraghty | Guest Star | Communion Girl | |
| Serena Terry | Guest Star | Officer Reid | |
| Ava Grace McAleese | Guest Star | Baby Anna | |
| Ardal O'Hanlon | Guest Star | Eammon | |
| Leah O'Rourke | Guest Star | Jenny Joyce | |
| Francis Mezza | Guest Star | Dee | |
| Sophie Brown | Guest Star | Baby Anna | |
| Julia Dearden | Guest Star | Maureen Malarkey | |
| Cara Quin | Guest Star | Communion Girl | |
| Vanessa Ifediora | Guest Star | Laurie | |
| Mya Rose McAleese | Guest Star | Baby Anna | |
| Bronagh Gallagher | Guest Star | The Commitment | |
| Beccy Henderson | Guest Star | Aisling | |
| Brenock O’Connor | Guest Star | Jon | |
| Zoe Brown | Guest Star | Baby Anna | |
| Amelia Crowley | Guest Star | Deirdre Mallon | |
| Conor O'Donnell | Guest Star | Waiter | |
| Cara Mailey | Guest Star | Little Girl | |
| Caoimhe Farren | Guest Star | Ms Taylor | |
| Liam Neeson | Guest Star | Chief Constable Byers | |
| Paul Mallon | Guest Star | Dennis | |
| Eleanor Methven | Guest Star | Aunt Bridie | |
| Desmond Eastwood | Guest Star | Benny | |
| Philippa Dunne | Guest Star | Geraldine Devlin | |
| James Stockdale | Guest Star | Tomas | |
| Bronagh Taggart | Guest Star | Intercom | |
| Chelsea Clinton | Guest Star | Chelsea Clinton | |
| Jay Duffy | Guest Star | Harry | |
| Claire Rafferty | Guest Star | Miss Mooney | |
| Michael Byers | Guest Star | Officer Lennox | |
| Conor Lowry | Guest Star | Young Boy | |
| Billy Carter | Guest Star | Mailman | |
| Robert Calvert | Guest Star | Jim | |
| Michael Lennox | Director |