 | Louis Ashbourne Serkis als Alexander "Alex" Elliot |
 | Dean Chaumoo als Bedders |
 | Tom Taylor als Lance |
 | Rhianna Dorris als Kaye |
 | Denise Gough als Mrs. Elliot |
 | Angus Imrie als Merlin |
 | Patrick Stewart als Old Merlin |
 | Rebecca Ferguson als Morgana |
 | Genevieve O'Reilly als Sophie |
 | Noma Dumezweni als Mrs. Lee |
 | Nathan Stewart-Jarrett als Mr. Kepler |
 | Mark Bonnar als Mr. Jeffreys |
 | Alexandra Roach als Ms. Foster |
 | Nick Mohammed als Mr. Hyde |
 | Adam Buxton als Stonehenge Tour Guide |
 | Claudie Blakley als Riding Instructor |
 | Myra McFadyen als Punto Patty |
 | Adam Leese als Policeman |
 | Joey Ansah als Policeman |
 | Amir Wilson als Boy (uncredited) |
| Joe Cornish | Director |
| Bill Pope | Director of Photography |
| Joe Cornish | Writer |
| Marcus Rowland | Production Design |
| Jany Temime | Costume Design |
| Jonathan Amos | Editor |
| Paul Machliss | Editor |
| Tim Bevan | Producer |
| James Biddle | Executive Producer |
| Eric Fellner | Producer |
| Nira Park | Producer |
| Rachael Prior | Executive Producer |
| Elizabeth Donker Curtius | Stunt Double |
| Electric Wave Bureau | Music |
| Nina Gold | Casting |
| Jessica Ronane | Casting |
| Simon Elsley | Art Direction |
| Jonathan Houlding | Art Direction |
| Katrina Mackay | Art Direction |
| Nigel Evans | Supervising Art Director |
| Sara Wan | Set Decoration |
| Niamh O'Loan | Key Makeup Artist |
| Claire Burgess | Key Hair Stylist |
| Jerry Ramsbottom | First Assistant Editor |
| Oscar Wright | Concept Artist |
| Frédéric Gaudin | VFX Artist |
| Nick Angel | Music Supervisor |
| Frazer Churchill | Visual Effects Supervisor |
| Peter White | Stunt Coordinator |
| Paul Jennings | Stunt Coordinator |
| Jonathan 'Chunky' Richmond | "A" Camera Operator |
| Jonathan 'Chunky' Richmond | Steadicam Operator |
| Chris Bain | "B" Camera Operator |
| Matt Windon | First Assistant "A" Camera |
| Russell Kennedy | First Assistant "B" Camera |
| Ian Jackson | Second Assistant "A" Camera |
| Harry Gamble | Second Assistant "B" Camera |
| Lisa MacGregor | Camera Loader |
| Ewan Sadler | Camera Trainee |
| Jay Patel | Digital Imaging Technician |
| Kerry Brown | Still Photographer |
| Richard Graysmark | First Assistant Director |
| Stewart Hamilton | Second Unit First Assistant Director |
| Paul Jennings | Second Unit Director |
| Tom Rye | Second Assistant Director |
| Fraser Fennell-Ball | Second Assistant Director |
| Colin Nicolson | Production Sound Mixer |
| Paula Casarin | Script Supervisor |
| Henry Kemplen | Visual Effects Editor |
| Rachael Havercroft | Post Production Coordinator |
| Eddie Knight | Gaffer |
| Lee Knight | Best Boy Electric |
| Malcolm Huse | Key Grip |
| Keith Mead | Best Boy Grip |
| Eugene McDonagh | Best Boy Grip |
| Alex Fraser | Grip |
| Ricky Hall | Grip |
| Emmet Cahill | Grip |
| Martin Mandeville | Costume Supervisor |
| Richard Davies | Assistant Costume Designer |
| Stephanie Hamilton-Jordan | Costume Coordinator |
| Sharon Martin | Makeup Designer |
| Sharon Martin | Hair Designer |
| Jill McCullough | Dialect Coach |
| Hephzibah Craen | Production Coordinator |
| Chloe Warren | Assistant Production Coordinator |
| Robbie Torbuck | Production Secretary |
| Betty Ainslie | Production Accountant |
| David Blank | Assistant Accountant |
| Rachel Limb | Payroll Accountant |
| Debbie Moseley | Assistant Accountant |
| Stuart Watson | Construction Manager |
| Stephanie Gibbins | Construction Coordinator |
| Claudia Kalindjian | Unit Publicist |
| Jeremy Price | Sound Designer |
| Jed Loughran | Sound Effects Editor |
| Luke O'Connell | Sound Editor |
| Matthew Skelding | Dialogue Editor |
| Hugo Adams | Foley Editor |
| Sophia Hardman | Foley Editor |
| Nina Norek | Assistant Sound Editor |
| Mark Appleby | ADR Mixer |
| Lottie Wade | ADR Recordist |
| Adam Mendez | Foley Mixer |
| Matt Dunkley | Conductor |
| Matt Dunkley | Orchestrator |
| Mark Baechle | Orchestrator |
| Tony Blondal | Orchestrator |
| Richard Bronskill | Orchestrator |
| Shaun O'Dell | Second Unit Director of Photography |
| Laura Richardson | Associate Producer |
| Emily Thomas | Third Assistant Director |
| Tolga Kenan | Stunts |
| Rob Bliss | Concept Artist |
