Cooper burst onto the International scene in 2001, scoring a try on his debut against Italy with only eight minutes left on the clock, and has gone on to win 40 caps for Wales, as well as touring New Zealand with the Lions in 2005.
He spent his early career with Bridgend before stints with Bath and the Celtic Warriors, The Dragons before joining Gloucester in 2007
In the 2008/09 season Cooper was selected by Warren Gatland for the Autumn Internationals and started against the three heavyweight southern hemisphere teams: South Africa, New Zealand and Australia.
Speaking of the signing Cardiff Blues Director of Rugby David Young said;
"Gareth has undoubtedly proven over the years that he is a quality scrum half and will be a great addition to our squad next season."
"There was obviously a lot of interest in him so it a real boost to us that he has chosen to join the Blues and I'm sure he will be another great addition to our squad."
"He performed admirably for Wales during the Autumn internationals and it's great that we are able to bring him back over the border."
As Cooper prepares to make the journey down the M50, Cardiff Blues outside half Nicky Robinson will be heading in the opposite direction, having signed with Gloucester RFC.
Speaking of the announcement Robinson said;
"It's obviously been one of the hardest decisions I'll ever have to make in my rugby career. To decide to leave my hometown club; somewhere where I dreamt of playing, and spent a large part of my career was always going to be hard."
"However, it's something I felt I needed to do. I wanted to experience playing in a different environment and a different league. I also wanted to test myself and try to improve as a rugby player and as a person, and Gloucester will give me that opportunity."
"I wanted to find out for myself what it is like to play in a different league and train with different players and coaches and change the routine that I have been doing for a number of years now."
"I've lived in Cardiff all my life and wanted to go to live in a different place so I will be looking to move up to Gloucester over the summer."
"I felt it was the right time for me but with the Blues going well in the Heineken Cup and EDF Cup, and the new training base and the new stadium, it made the decision a lot harder."
"I'd like to thank the Blues for being very loyal to me throughout my time here; they've really stuck by me when I've had injuries and illnesses."
"I've got a very good relationship with Dai, and have huge amount of respect for him, not only as a coach but also as a really decent person. So it was very hard to tell him, knowing how much effort he has put into building up the Blues."
"The supporters club have also been great to me, and hopefully I've repaid them by giving everything every time I've worn the blue shirt and have been very proud of putting that jersey on which will remain the case until the end of what I hope will be a successful season.''
"My mother is devastated at the news as all three sons will be leaving next season. I'll be moving to Gloucester, Jamie's moving to France and my younger brother is hoping to go away to University. But on a positive note it frees up her weekends."
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