| Name | Character | Episodes |
|---|---|---|
| Sullivan Stapleton | Sgt. Damien Scott | 40 |
| Philip Winchester | Sgt. Michael Stonebridge | 40 |
| Michelle Lukes | Sgt. Julia Richmond | 40 |
| Warren Brown | Sergeant Daniel “Mac” Macallister | 30 |
| Daniel MacPherson | Sergeant Samuel Wyatt | 30 |
| Alin Sumarwata | Lance Corporal Gracie Novin | 30 |
| Rhona Mitra | Maj. Rachel Dalton | 20 |
| Jamie Bamber | Col. Alexander Coltrane | 20 |
| Liam Garrigan | Sgt. Liam Baxter | 20 |
| Rhashan Stone | Major Oliver Sinclair | 20 |
| Richard Armitage | John Porter | 16 |
| Yasemin Kay Allen | Katrina Zarkova | 13 |
| Michelle Yeoh | Mei Foster | 10 |
| Charles Dance | Conrad Knox | 10 |
| Vincent Regan | Karl Matlock | 10 |
| Roxanne McKee | Captain Natalie Reynolds | 10 |
| Nina Sosanya | Colonel Adeena Donovan | 10 |
| Stephanie Vogt | Christy Bryant | 10 |
| Jimi Mistry | Maj. Jamal Ashkani / Latif | 10 |
| Robson Green | Lt. Col. Philip Locke | 10 |
| Eva Birthistle | Captain Kate Marshall | 10 |
| Amanda Mealing | Col. Eleanor Grant | 10 |
| Lyne Renee | Rebecca | 10 |
| Varada Sethu | LCpl. Manisha Chetri / Chetri | 10 |
| Phil Dunster | LCpl. Will Jensen | 8 |
| Andrew Lincoln | Hugh Collinson | 6 |
| Jodhi May | Layla Thompson | 6 |
| Colin Salmon | James Middleton | 6 |
| Shelley Conn | Danni Prendiville | 6 |
| Orla Brady | Katie Dartmouth | 6 |
| Nicola Stephenson | Diane Porter | 6 |
| Laura Greenwood | Alexandra "Lexie" Porter | 6 |
| Alyy Khan | Major General Kohli | 3 |
| Annabelle Wallis | Dana Van Rijn | 2 |
| Iain Glen | Gerald Crawford | 2 |
| Eamonn Walker | Walter Lutulu | 2 |
| Alexander Siddig | Zahir Sharq | 2 |
| Karen David | Barmaid | 2 |
| Max Beesley | Ray McQueen | 2 |
| Attila Árpa | Laszlo | 2 |
| Tim Pigott-Smith | Patrick Burton | 2 |
| Peter O'Meara | Maj. Brian Donoghue | 2 |
| Mark Strepan | Josef Varga | 2 |
| Brian Milligan | Teague | 2 |
| Matthew Leitch | Kennedy | 2 |
| Faizal Hussein | Hassan Ahmed | 2 |
| Catherine Walker | Mairead McKenna | 1 |
| Nina Seničar | Elvanna | 1 |
| Maxim Baldry | Loric Demachi | 1 |
| Rhianne Barreto | Maya | 1 |
| Vithaya Pansringarm | Chanrok | 1 |
| Martin Wimbush | Vicar | 1 |
| Pallavi Sharda | Samira Shah | 1 |
| Akira Koieyama | Akiyama | 1 |
| Ky Discala | SOPHIA | 1 |
| Jimi Mistry | Latif | 0 |