"I do owe a big thank you to Cardiff City for what they did for me during my time there," Koumas told the Western Mail.
"I really enjoyed playing at Ninian Park, with a good bunch of players and a fantastic manager in Dave Jones.
"It was great playing for such a good manager. I have to credit him really for helping me get everything back on track."
Koumas' W.B.A. side are competing with Cardiff City in the race for the Premiership.