- John Hurt
- Â The Dragon 65 episodes, 2008-2012
- Colin Morgan
- Â Merlin 65 episodes, 2008-2012
- Bradley James
- Â Arthur 65 episodes, 2008-2012
- Richard Wilson
- Â Gaius 65 episodes, 2008-2012
- Angel Coulby
- Â Gwen 65 episodes, 2008-2012
- Katie McGrath
- Â Morgana 65 episodes, 2008-2012
- Anthony Head
- Â Uther Pendragon 43 episodes, 2008-2012
- Rupert Young
- Â Sir Leon 39 episodes, 2009-2012
- Eoin Macken
- Â Sir Gwaine / ... 30 episodes, 2010-2012
- Tom Hopper
- Â Sir Percival 26 episodes, 2010-2012
- Tomiwa Edun
- Â Sir Elyan / ... 21 episodes, 2010-2012
- Nathaniel Parker
- Â Agravaine 13 episodes, 2011
- Michael Cronin
- Â Geoffrey of Monmouth 12 episodes, 2008-2011
- Emilia Fox
- Â Morgause 11 episodes, 2009-2011
- Alexander Vlahos
- Â Mordred 11 episodes, 2012
- Santiago Cabrera
- Â Lancelot 6 episodes, 2008-2011
- Michelle Ryan
- Â Nimueh 4 episodes, 2008
- Caroline Faber
- Â Hunith 4 episodes, 2008-2011
- Tom Ellis
- Â Cenred 4 episodes, 2010
- Asa Butterfield
- Â Mordred 3 episodes, 2008-2009
- Trevor Sellers
- Â Iseldir 3 episodes, 2008-2011
- Alice Patten
- Â Ygraine 3 episodes, 2009-2010
- Terence Maynard
- Â Helios 3 episodes, 2011
- Rhys Rusbatch
- Â The Guard 3 episodes, 2009
- Zee Asha
- Â Audrey 3 episodes, 2011-2012
- Fintan McKeown
- Â King Odin 2 episodes, 2009-2012
- Sarah Parish
- Â Lady Catrina 2 episodes, 2009
- Adam Godley
- Â Jonas 2 episodes, 2009
- David Durham
- Â Tom 2 episodes, 2008
- Gary Lewis
- Â Alator 2 episodes, 2011-2012
- Sophie Rundle
- Â Sefa 2 episodes, 2012
- Michael Jenn
- Â Sidhe Elder 2 episodes, 2008-2010
- Simon Nehan
- Â Tom 2 episodes, 2009-2010
- Laura Donnelly
- Â Freya 2 episodes, 2009-2010
- Duncan Meadows
- Â Ewan / ... 2 episodes, 2010-2011
- Calum MacPherson
- Â Evoric 2 episodes, 2010
- Maureen Carr
- Â The Dochraid 2 episodes, 2011-2012
- Ben Daniels
- Â Tristan 2 episodes, 2011
- Janet Montgomery
- Â Princess Mithian 2 episodes, 2011-2012
- Gary Oliver
- Â Gregory 2 episodes, 2008
- Miranda Raison
- Â Isolde 2 episodes, 2011
- Rick English
- Â Black Knight / ... 2 episodes, 2008
- Barry Aird
- Â Beroun 2 episodes, 2012
- Erin Richards
- Â Eira 2 episodes, 2012
- Ed Coleman
- Â Morris 2 episodes, 2008
- Jake Phillips
- Â Ghost Boy 2 episodes, 2010
- Stephen McCole
- Â Ragnor 2 episodes, 2012
- John Lynch
- Â Balinor 2 episodes, 2009-2012
- Liam Cunningham
- Â Ruadan 2 episodes, 2012
- Josette Simon
- Â The Euchdag 2 episodes, 2012
- Lindsay Duncan
- Â Queen Annis 2 episodes, 2011-2012
- James Greene
- Â Ferryman 2 episodes, 2011
- Kyle Lima
- Â Caerleon's Guard / ... 2 episodes, 2011
- Gemma Jones
- Â The Cailleach 2 episodes, 2011
- John Bradley
- Â Tyr Seward 1 episode, 2012
- Alexander Siddig
- Â Kanen 1 episode, 2008
- Julian Rhind-Tutt
- Â Edwin 1 episode, 2008
- Will Mellor
- Â Knight Valiant 1 episode, 2008
- Alun Raglan
- Â Cerdan 1 episode, 2008
- Richard Ridings
- Â Halig 1 episode, 2009
- Jonathan Bryan
- Â Sir Radnor 1 episode, 2009
- Harry Melling
- Â Gilli 1 episode, 2010
- Pauline Collins
- Â Alice 1 episode, 2010
- James Callis
- Â Borden 1 episode, 2011
- Wayne Foskett
- Â John Howden 1 episode, 2011
- Peter Guinness
- Â Ari 1 episode, 2012
- Frances Tomelty
- Â Niede 1 episode, 2012
- Alfie Stewart
- Â Daegel 1 episode, 2012
- Holliday Grainger
- Â Sophia 1 episode, 2008
- Joe Dempsie
- Â William 1 episode, 2008
- Andy Linden
- Â Devlin 1 episode, 2008
- Joseph Mawle
- Â Alvarr 1 episode, 2009
- Jack Sandle
- Â Kelda 1 episode, 2009
- Jem Wall
- Â Joseph 1 episode, 2009
- Victoria Finney
- Â Cathryn 1 episode, 2009
- Eddie Marsan
- Â The Manticore 1 episode, 2010
- Georgia King
- Â Princess Elena 1 episode, 2010
- Ian Burfield
- Â Nollar 1 episode, 2010
- Steven Hartley
- Â Caerleon 1 episode, 2011
- Melanie Hill
- Â Mary Howden 1 episode, 2011
- Sian Thomas
- Â Atorloppe 1 episode, 2012
- Frank Finlay
- Â Anhora 1 episode, 2008
- Jonathan Aris
- Â Matthew 1 episode, 2008
- Cal MacAninch
- Â Tauren 1 episode, 2008
- Michael Burgess
- Â Stallholder 1 episode, 2008
- Nicholas Gasson
- Â Steward 1 episode, 2008
- Emily Beecham
- Â Enmyria 1 episode, 2009
- David Schofield
- Â King Alined 1 episode, 2009
- Adrian Lester
- Â Myror 1 episode, 2009
- Justin Avoth
- Â Sir Robert 1 episode, 2009
- Mark Williams
- Â The Goblin 1 episode, 2010
- Simon Williams
- Â Lord Godwyn 1 episode, 2010
- Karl Johnson
- Â Taliesin 1 episode, 2010
- Jody Halse
- Â Fermin 1 episode, 2010
- Paul McNeilly
- Â Tindr 1 episode, 2010
- Sarah Counsell
- Â Mary 1 episode, 2010
- Phil Davis
- Â The Gleeman 1 episode, 2011
- Helen Schlesinger
- Â Befelan 1 episode, 2012
- Jane Thorne
- Â Valdis 1 episode, 2012
- Eve Myles
- Â Lady Helen / ... 1 episode, 2008
- Jamie Kenna
- Â Guard 1 1 episode, 2008
- Kevin Eldon
- Â Trickler 1 episode, 2009
- Miriam Margolyes
- Â Grunhilda 1 episode, 2010
- Andrew Vincent
- Â Dagr 1 episode, 2010
- Phil Holden
- Â Geldred 1 episode, 2011
- James Fox
- Â King Rodor 1 episode, 2012
- Andrew Tiernan
- Â Osgar 1 episode, 2012
- Gordon Munro
- Â Alrick 1 episode, 2012
- Kenneth Cranham
- Â Aulfric 1 episode, 2008
- Christian Bradley
- Â Guard 2 1 episode, 2008
- Mark Lewis Jones
- Â King Olaf 1 episode, 2009
- Chris McGill
- Â Guard 1 episode, 2009
- Shend
- Â Ebor 1 episode, 2010
- Clive Russell
- Â Bayard 1 episode, 2008
- Ben Adams
- Â Bandit 1 episode, 2008
- Mackenzie Crook
- Â Cedric 1 episode, 2009
- Georgia Tennant
- Â Lady Vivian 1 episode, 2009
- Michael Nardone
- Â Kendrick 1 episode, 2009
- Richard Riddell
- Â Evan 1 episode, 2008
- Charles Dance
- Â Aredian 1 episode, 2009
- Jonny Coyne
- Â Asgerd 1 episode, 2009
- Michael Ballard
- Â Bandit 1 episode, 2009
- Nicholas Croucher
- Â Druid Boy 1 episode, 2011
- Alexandra Dowling
- Â Kara 1 episode, 2012
- Beth Cordingly
- Â Forridel 1 episode, 2009
- Alexander Delamere
- Â Innkeeper 1 episode, 2009
- Bill Thomas
- Â Cylferth 1 episode, 2010
- Sarah Beck Mather
- Â The Vilia 1 episode, 2011
- John Shrapnel
- Â The Sarrum 1 episode, 2012
- Veronica Roberts
- Â Gelda Seward 1 episode, 2012
- Christopher Fairbank
- Â Voice of the Black Knight 1 episode, 2008
- Keith Thorne
- Â Ewan 1 episode, 2008
- Colin Salmon
- Â Aglain 1 episode, 2009
- Alex Price
- Â William 1 episode, 2009
- Luke Neal
- Â Sir Geraint 1 episode, 2009
- Katie Foster-Barnes
- Â Beatrice 1 episode, 2009
- Ian Peck
- Â Althild 1 episode, 2010
- Jamie McKenna
- Â Dungeon Guard 1 episode, 2008
- Kyle Redmond-Jones
- Â Sir Owain 1 episode, 2008
- James Cosmo
- Â Hengist 1 episode, 2009
- Amanda Fairbank-Hynes
- Â Annie 1 episode, 2009
- Brian Peck
- Â Eldred 1 episode, 2009
- Warwick Davis
- Â Grettir 1 episode, 2010
- Philip Brodie
- Â Sir Ethan 1 episode, 2010
- Grahame Fox
- Â Rider 1 episode, 2010
- Matthew Barker
- Â Guard 1 episode, 2010
- Leander Deeny
- Â George 1 episode, 2011
- Sorcha Cusack
- Â Finna 1 episode, 2012
- Kelly Wenham
- Â Queen Mab 1 episode, 2012
- Louise Dylan
- Â Bronwen 1 episode, 2008
- Paul Kynman
- Â Sir Cador 1 episode, 2008
- Sean Francis
- Â Sir Pellimor 1 episode, 2008
- James Armstrong
- Â Guard No. 1 1 episode, 2009
- Samara MacLaren
- Â Rowena 1 episode, 2009
- John Hopkins
- Â Sir Oswald 1 episode, 2010
- Donald Sumpter
- Â The Fisher King 1 episode, 2010
- Gemma Arrowsmith
- Â Rose 1 episode, 2010
- Charlene McKenna
- Â Lamia 1 episode, 2011
- Tom Meredith
- Â Eoghan 1 episode, 2011
- Tony Guilfoyle
- Â Sindri 1 episode, 2012
- Mike Goodenough
- Â Fyren 1 episode, 2009
- Ralph Ineson
- Â Jarl 1 episode, 2010
- Jonny Emmett
- Â Inn Keeper 1 episode, 2010
- Julian Glover
- Â Lochru 1 episode, 2012
- Matthew Clancy
- Â Albin 1 episode, 2012
- David Sterne
- Â The Apothecary 1 episode, 2009
- Matthew Crawford
- Â Bandit 1 episode, 2010
- Gareth Jewell
- Â Helios' Servant 1 episode, 2011
- Mitch Benn
- Â Gerrin 1 episode, 2012
- Raul Griffiths
- Â Druid Boy 1 episode, 2010
- Robert Maillet
- Â Derian 1 episode, 2011
- Giles New
- Â Guard 1 episode, 2012
- Katie Moore
- Â Drea 1 episode, 2011
- Hugh Holman
- Â Camelot Guard (uncredited) 5 episodes, 2008-2012
- Philip John Bailey
- Â Knight (uncredited) 4 episodes, 2012
- Mylène Ragon
- Â Clown / ... (uncredited) 3 episodes, 2009-2012
- Simon Pengelly
- Â Bandit (uncredited) 3 episodes, 2009-2011
- Darren Swain
- Â Saxon swordsman / ... (uncredited) 3 episodes, 2012
- Simon Blood DeVay
- Â Camelot Guard / ... (uncredited) 2 episodes, 2009-2010
- Greg Bennett
- Â Council Elder (uncredited) 2 episodes, 2011
- Adrian Mitchell
- Â Southron Warrior (uncredited) 2 episodes, 2011
- Sy Turner
- Â Camelot Knight (uncredited) 2 episodes, 2011
- Vincent Lecrocq
- Â Southron Warrior (uncredited) 2 episodes, 2011
- Mickey Lewis
- Â Odin's Man / ... (uncredited) 2 episodes, 2012
- Alan Bond
- Â Castle Guard (uncredited) 1 episode, 2008
- Matthew Rohman
- Â Villager (uncredited) 1 episode, 2008
- Samantha E. Hunt
- Â Paganum (uncredited) 1 episode, 2008
- Leigh Stevenson
- Â Palace Guard (uncredited) 1 episode, 2008
- Paul Robert Bird
- Â One of the Order of Four (uncredited) 1 episode, 2008
- John Hutch
- Â Guard (uncredited) 1 episode, 2009
- Michael Chase
- Â Messenger (uncredited) 1 episode, 2009
- Matthew Jones
- Â Thug Hit with Jug (uncredited) 1 episode, 2010
- John Ninnis
- Â Camelot Knight (uncredited) 1 episode, 2011
- William Charles
- Â Camelot Knight (uncredited) 1 episode, 2011
- Robert Moir
- Â Mercenary (uncredited) 1 episode, 2011
- Jamie Oliver-Jones
- Â Guard (uncredited) 1 episode, 2012
- Eran Backler
- Â Worker (uncredited) 1 episode, 2012