The Celtic Crusaders, as they were then known, were founded in 2005 and first entered National League Two in 2006. In 2009 they started playing in Super League and in 2010 moved from Bridgend to play in Wrexham.
Gareth joined the Crusaders on Friday 5th of March and becomes arguably the highest profile Welsh player to change codes since rugby union turned professional in 1995.
Speaking of announcement Cardiff Blues Director of Rugby, David Young said,
"We would like to thank Gareth for his contribution to the Cardiff Blues over the last three years."
"He is a larger than life character but is still totally professional and dedicated to his sport."
"He has kept himself in great shape and has been a great help in bringing on young players."
"His versatility has also been invaluable to us during his time here."
"We would like to wish him the best of luck in this new chapter of his rugby career."
"It's probably fair to say that Gareth has given his all to Welsh rugby."
"He requested that he could join the Crusaders as early as possible because their season had just started and we felt it was only fair to let him go with immediate effect to pursue this fresh challenge."
"As someone who played both codes, I know the type of challenges that Gareth will face."
"Knowing Gareth as I do, he will meet these challenges head on, and I'm sure he will be a success at playing rugby league."
Blues Chief Executive, Robert Norster added;
"Besides being a huge on and off the field presence for the Blues and before that Cardiff RFC, Gareth has been an outstanding servant of Welsh Rugby."
"He will rightly remain a modern day legend of our national sport with many life-long friends and supporters here who all wish him every success in this final chapter of his long and illustrious sporting career".
Gareth Thomas added,
"I've loved my time at the Blues and when I joined I felt I was joining a massive family both off and on the field."
"Everyone has been great to me: the fans, coaches, the squad and the off field staff, they have all been superb."
"I will have a lot of special memories from my time with them."
"Bridgend will always be my hometown club but the Blues will always hold a special place in my heart."
"It's sad to leave, but I'm hugely excited about joining the Crusaders".
"Brian Noble is an inspirational figure so I'm looking forward to working with him."
"I'll also be working closely with Iestyn Harris, who will be helping me to understand the game."
"I wanted something that would challenge me and I've always accepted any challenge that has been put in front of me."
"People may say it's the wrong time in my career, however, I feel that it's right for me."
"It may have been the easy option to carry on in union but I'm looking forward to the challenge and there certainly aren't any hiding places in rugby league."
"I'm not doing it just for the money as it's a vicious league and I want to really test myself."
"I've never played League before but I imagine the biggest difference will be the instincts."
"You can learn the rules but things that you may do instinctively in union you don't in league and vice versa."
"Having not played the game, in a way I'm going into it blind, but I'm excited by it, having always admired it when I've watched the games on TV."