Gareth David-Lloyd

as Mark

as Andy Fairbrother(1 ep)

as Gethin(2 eps)

as Emlyn Williams

as Captain Mordial(1 ep)

as Matt(1 ep)

as Green

as Prince Albert

as Ben

as Jacob Fitts

as Dr. John Watson

as Matheson(6 eps)

as Mr. Wolcott(1 ep)

as Ianto Jones(31 eps)

as Rob Hutchinson(3 eps)

as Ianto Jones(2 eps)

as Yanto Jones(1 ep)

as Zack(1 ep)

as Darrell Kemmer(1 ep)