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 | ||
| Michael Byers | Guest Star | Officer Lennox | |
| Desmond Eastwood | Guest Star | Benny | |
| Billy Carter | Guest Star | Mailman | |
| Philippa Dunne | Guest Star | Geraldine Devlin | |
| Bronagh Taggart | Guest Star | Intercom | |
| Laurie Kynaston | Guest Star | Philip | |
| Chelsea Clinton | Guest Star | Chelsea Clinton | |
| Claire Rafferty | Guest Star | Miss Mooney | |
| Serena Terry | Guest Star | Officer Reid | |
| Conor Lowry | Guest Star | Young Boy | |
| Ava Grace McAleese | Guest Star | Baby Anna | |
| Robert Calvert | Guest Star | Jim | |
| Art Campion | Guest Star | Father Peter | |
| Francis Mezza | Guest Star | Dee | |
| Donna Traynor | Guest Star | Donna Traynor | |
| Kevin McAleer | Guest Star | Uncle Colm | |
| Vanessa Ifediora | Guest Star | Laurie | |
| Clara Geraghty | Guest Star | Communion Girl | |
| Mya Rose McAleese | Guest Star | Baby Anna | |
| Ardal O'Hanlon | Guest Star | Eammon | |
| Leah O'Rourke | Guest Star | Jenny Joyce | |
| Brenock O’Connor | Guest Star | Jon | |
| Sophie Brown | Guest Star | Baby Anna | |
| Conor O'Donnell | Guest Star | Waiter | |
| Julia Dearden | Guest Star | Maureen Malarkey | |
| Caoimhe Farren | Guest Star | Ms Taylor | |
| Cara Quin | Guest Star | Communion Girl | |
| Bronagh Gallagher | Guest Star | The Commitment | |
| Beccy Henderson | Guest Star | Aisling | |
| Eleanor Methven | Guest Star | Aunt Bridie | |
| Zoe Brown | Guest Star | Baby Anna | |
| James Stockdale | Guest Star | Tomas | |
| Amelia Crowley | Guest Star | Deirdre Mallon | |
| Cara Mailey | Guest Star | Little Girl | |
| Jay Duffy | Guest Star | Harry | |
| Liam Neeson | Guest Star | Chief Constable Byers | |
| Paul Mallon | Guest Star | Dennis | |
| Michael Lennox | Director |