Rees made his debut for Wales against the USA in 2005 and has gone on to win 57 caps for his country.
He was also selected for the Lions tour to South Africa in 2009, playing in all three Tests, and started alongside fellow Welsh front-row internationals Gethin Jenkins and Adam Jones in the Second Test.
“Leaving the Scarlets has been a tough decision to make after being there for so many years,” said Rees. “The Scarlets is where I established myself as a player however I feel that this is the right decision at this point in my career.
“For me personally, I feel that moving to the Blues will provide me with a fresh, new challenge that I am ready to tackle.
“From working with Phil in the past, I know he is a very organised coach and knows how to get the best out of players and I am looking forward to working with him again. I think he was frustrated with some of the results this season but the hard work is paying off with some performances and results recently. The win out in Munster shows what this team can do.
“It’s good that the Blues are bringing through the youngsters and with some key signings to strengthen the squad, I’m sure there will be more to come from the team.
“The Blues have had success over recent years but have since lost a lot of experienced players such as Martyn Williams, Gethin Jenkins and Xavier Rush who are difficult to replace.
“However, so far this season, I have been really impressed with the young players that Phil has brought through and now with some key signings to strengthen the squad.
“I’m sure there will be more success to come from the team, which with my experience I hope to contribute to.”
Having been raised in Tonyrefail, Rees played for the Celtic Warriors and Pontypridd before joining the Scarlets in 2004 and going on to make more than 150 appearances.
“I’m obviously from the Blues region originally and when the Celtic Warriors disbanded I think there was interest in signing me but I moved to the Scarlets.
“Joining the Blues at this stage in my career will, I hope, freshen things up for me as I’ve still got ambitions to play for Wales.”
