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