The midfielder had two years left to run but has now had another 12 months tagged on.
The 31-year-old has made 467 appearances for the Swans since signing for them in 2002, with his only break coming with a brief spell at Sheffield United.
"To stay on at the club for an extra year on top of my current contract is something that I am delighted to do," he said
"From a personal point of view, the contract talks these days are so easy
I just wanted to get it done.
"To get to 500 appearances in all competitions would be a great achievement for me
That's my next personal target.
"But the important thing is that I help the club stay in the Premier League
We have had three years in the Premier League and I'd be delighted if we are still in it at the end of my new contract."
Source : PA
Source: PA