Jones joins Cardiff after snubbing Ospreys
Wales's prop Adam Jones (R) runs with the ball during the Six Nations international rugby union match between Wales and England at the Millennium Stadium in Cardiff, on March 16, 2013 - by Paul Ellis
"Adam has joined the Blues determined to achieve something special with us. He is as hungry as ever for success and a very driven man," said Cardiff's director of rugby Mark Hammett.
Jones, 33, made his Wales debut in 2003 and was a member of the team that won the Six Nations Grand Slam in 2005, 2008 and 2013. He was also a member of the British and Irish Lions squad that triumphed in Australia last year.
"This is about a new challenge for me. At this stage in my career, I want a new environment and to really push myself," Jones said.
Cardiff did not specify the length of Jones's contract, but he is reported to have agreed a one-year deal.
Jones added: "I've been really impressed by the set-up at Blues and the desire to achieve in the coming years under the leadership of Mark Hammett. It is that ambition and potential for the future that excites me about this move.
"Obviously I would like to thank everyone at the Ospreys -- from the players and coaches to the wonderful supporters -- who have been absolutely fantastic with me. I wish the region every success for the future."
Jones's agents, Big Red Management, had announced the move on their Twitter account earlier on Tuesday, writing: "All parties delighted that @adamjones3 has signed with @cardiff_blues."
The tweet was accompanied by a picture of Jones apparently signing his Blues contract at Cardiff Arms Park.
The shaggy-haired tighthead, who has won 95 caps for Wales, had been with the Ospreys since 2003.
He had been training with formative club Neath after his Ospreys contract expired at the end of last season.
In a statement, the Ospreys said they were "disappointed" by Jones's decision not to accept their offer of a new deal.
"Adam Jones has today (Tuesday) advised Ospreys Rugby that he will not be re-signing and instead has signed a contract with another region," the club said.
"We are disappointed with this outcome, having worked closely with Adam over a period of many months to find a resolution to the situation that satisfied all parties."
The Ospreys' talks with Jones were complicated by an ongoing dispute between the Welsh Rugby Union (WRU) and the four Welsh regions -- Blues, Ospreys, Newport-Gwent Dragons and Scarlets -- over a new participation agreement.