| Name | Character | Episodes |
|---|---|---|
| Nicola Walker | DI Annika Strandhed | 12 |
| Katie Leung | DC Blair Ferguson | 12 |
| Jamie Sives | DS Michael McAndrews | 12 |
| Ukweli Roach | DS Tyrone Clarke | 9 |
| Kate Dickie | DCI Diane Oban | 7 |
| Paul McGann | Jake Strathearn | 6 |
| Varada Sethu | DC Harper Weston | 4 |
| Rebecca Root | Alex Carrigan | 1 |
| Christy O'Donnell | Danny Hendry | 1 |
| Thoren Ferguson | Lee Tanner | 1 |
| Russ Bain | Greg Connolly | 1 |
| Matt Costello | Salty Stewart | 1 |
| Vivien Taylor | Leila | 1 |
| Lewis Howden | Rab Sterling | 1 |
| Shauna Macdonald | Liz Dunbar | 1 |
| Tam Dean Burn | PS Tam Glenn | 1 |
| Marnie Baxter | Karina Williams | 1 |
| Ryan Bown | Andros Bakas | 1 |
| Caroline Guthrie | Isla Hendry | 1 |
| Kim Allan | Heidi Greenshields | 1 |
| James Anthony Pearson | Lance Wallace | 1 |
| Shona McHugh | Denise | 1 |
| Pal Aron | Rihan Harijan | 1 |
| Gavin Mitchell | Lachie Nevin | 1 |
| Gabriel Quigley | Nell Dwight | 1 |
| Laura Ferries | Briony Craig | 1 |
| Moyo Akandé | Mel Hetherington | 1 |
| Martin Bell | Stuart Straney | 1 |
| Maryam Hamidi | Dana Ashraf | 1 |
| Mel Raido | Agamemnon 'Mem 'Yiannopoulos | 1 |
| Dom Watters | Casper McCray | 1 |
| Anita Vettesse | Carmela MacGowan | 1 |
| Paul McCole | Mitch McAskill | 1 |
| Dyfan Dwyfor | Neil Kelly | 1 |
| Billy Mack | Bruce Kerr | 1 |
| Gail Watson | Maggie Fisher | 1 |
| Seylan Baxter | Senga McCauley | 1 |