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