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