| Companion Name | Actor/Actress |
| Gemma Griffin | Lizzie Hopley |
| Samson Griffin | Lee Ingleby |
| Charlotte Pollard | India Fisher |
| C'rizz | Conrad Westmaas |
| Lucie Miller | Sheridan Smith |
| Tamsin Drew | Niky Wardley |
| Molly O'Sullivan | Ruth Bradley |
| Liv Chenka | Nicola Walker |
| Mary Shelley | Julie Cox |
| Fitz Kreiner | Matt di Angelo |
| Izzy Sinclair | Jemima Rooper |
| Bernice Summerfield | Lisa Bowerman |
| Brigadier General Sir Alistair Gordon Lethbridge-Stewart | Nicholas Courtney |
| Sergeant Andy Davidson | Tom Price |
| Tania Bell | Rebecca Root |
| Helen Sinclair | Hattie Morahan |
| It is always possible that more companions | /friends may appear in future stories |