- Ep: 1
- The Dragon's Call
- Cast in Order of Appearance: Colin Morgan (Merlin), John Hurt (Voice of the Dragon), Anthony Head (Uther Pendragon), Katie McGrath (Morgana), Eve Myles (Mary Collins / Lady Helen), Richard Wilson (Gaius), Caroline Faber (Hunith), Gary Oliver (Gregory), Bradley James (Arthur), Ed Coleman (Morris), Angel Coulby (Gwen), Louise Dylan (Bronwen)
- Written By: Julian Jones
- Directed By: James Hawes
- Ep: 2
- Valiant
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Will Mellor (Knight Valiant), Andy Linden (Devlin), Nicholas Gasson (Steward), Colin Morgan (Merlin), Bradley James (Arthur), Richard Wilson (Gaius), Angel Coulby (Gwen), Katie McGrath (Morgana), Keith Thorne (Ewan), Anthony Head (Uther Pendragon), Ed Coleman (Morris)
- Written By: Howard Overman
- Directed By: James Hawes
- Ep: 3
- The Mark of Nimueh
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Michelle Ryan (Nimueh), Colin Morgan (Merlin), Richard Wilson (Gaius), Angel Coulby (Gwen), David Durham (Tom), Katie McGrath (Morgana), Anthony Head (Uther Pendragon), Bradley James (Arthur), Rick English (The Afanc)
- Written By: Julian Jones
- Directed By: James Hawes
- Ep: 4
- The Poisoned Chalice
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Michelle Ryan (Nimueh), Colin Morgan (Merlin), Anthony Head (Uther Pendragon), Bradley James (Arthur), Clive Russell (Bayard), Richard Wilson (Gaius), Angel Coulby (Gwen), Katie McGrath (Morgana), Gary Oliver (Gregory), Jamie Kenna (Dungeon Guard), Paul Kynman (Sir Cador)
- Written By: Ben Vanstone
- Directed By: Ed Fraiman
- Ep: 5
- Lancelot
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Colin Morgan (Merlin), Santiago Cabrera (Lancelot), Richard Wilson (Gaius), Anthony Head (Uther Pendragon), Bradley James (Arthur), Michael Cronin (Geoffrey of Monmouth), Angel Coulby (Gwen), Katie McGrath (Morgana)
- Written By: Jake Michie
- Directed By: Ed Fraiman
- Ep: 6
- A Remedy to Cure All Ills
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Julian Rhind-Tutt (Edwin), Katie McGrath (Morgana), Angel Coulby (Gwen), Richard Wilson (Gaius), Anthony Head (Uther Pendragon), Colin Morgan (Merlin), Bradley James (Arthur), Michael Cronin (Geoffrey of Monmouth)
- Written By: Julian Jones
- Directed By: Ed Fraiman
- Ep: 7
- The Gates of Avalon
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Bradley James (Arthur), Holliday Grainger (Sophia), Katie McGrath (Morgana), Colin Morgan (Merlin), Kenneth Cranham (Aulfric), Ben Adams (Bandit), Anthony Head (Uther Pendragon), Richard Wilson (Gaius), Angel Coulby (Gwen), Michael Jenn (Sidhe Elder)
- Written By: Ben Vanstone
- Directed By: Jeremy Webb
- Ep: 8
- The Beginning of the End
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Alun Kaglan (Cerdan), Asa Butterfield (Mordred), Michael Burgess (Stallholder), Jamie Kenna (Guard 1), Christian Bradley (Guard 2), Colin Morgan (Merlin), Katie McGrath (Morgana), Angel Coulby (Gwen), Bradley James (Arthur), Anthony Head (Uther Pendragon), Richard Wilson (Gaius), Trevor Sellers (Iseldir)
- Written By: Howard Overman
- Directed By: Jeremy Webb
- Ep: 9
- Excalibur
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Michelle Ryan (Nimueh), Bradley James (Arthur), Anthony Head (Uther Pendragon), Katie McGrath (Morgana), Colin Morgan (Merlin), Angel Coulby (Gwen), Richard Wilson (Gaius), Rick English (Black Knight), Christopher Fairbank (Voice of the Black Knight), Kyle Redmond-Jones (Sir Owain), Sean Francis (Sir Pellinor), Michael Cronin (Geoffrey of Monmouth)
- Written By: Julian Jones
- Directed By: Jeremy Webb
- Ep: 10
- The Moment of Truth
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Alexander Siddig (Kanen), Joe Dempsie (William), Jonathan Aris (Matthew), Richard Wilson (Gaius), Caroline Faber (Hunith), Colin Morgan (Merlin), Anthony Head (Uther Pendragon), Bradley James (Arthur), Katie McGrath (Morgana), Angel Coulby (Gwen)
- Written By: Ben Vanstone
- Directed By: David Moore
- Ep: 11
- The Labyrinth of Gedref
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Bradley James (Arthur), Colin Morgan (Merlin), Frank Finlay (Anhora), Anthony Head (Uther Pendragon), Richard Wilson (Gaius), Angel Coulby (Gwen), Richard Riddell (Evan), Katie McGrath (Morgana)
- Written By: Howard Overman
- Directed By: Stuart Orme
- Ep: 12
- To Kill the King
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), David Durham (Tom), Angel Coulby (Gwen), Cal Macaninch (Tauren), Colin Morgan (Merlin), Bradley James (Arthur), Richard Wilson (Gaius), Katie McGrath (Morgana), Anthony Head (Uther Pendragon)
- Written By: Jake Michie
- Directed By: Stuart Orme
- Ep: 13
- Le Morte d'Arthur
- Cast in Order of Appearance: John Hurt (Voice of the Dragon), Bradley James (Arthur), Colin Morgan (Merlin), Richard Wilson (Gaius), Anthony Head (Uther Pendragon), Katie McGrath (Morgana), Angel Coulby (Gwen), Michelle Ryan (Nimueh), Caroline Faber (Hunith)
- Written By: Julian Jones
- Directed By: David Moore
| Colin Morgan .............................. Merlin |
| Angel Coulby ................................ Gwen |
| Bradley James ............ Prince Arthur Pendragon |
| Katie McGrath ............................ Morgana |
| Anthony Head ................ King Uther Pendragon |
| Richard Wilson ............................. Gaius |
| John Hurt .......... The Voice of the Great Dragon |
