The 33-year-old's long association with Newcastle United came to an end this summer following the expiration of his contract.
Joining the Magpies' Academy at the aged of nine, Dummett made his senior debut in January 2013 and went on to amass 213 competitive appearances, scoring on four occasions.
He has now penned a deal until early January with the Latics, who are in League One and managed by former Scotland international Shaun Maloney.
He told his new club's official website: "Signing for Wigan Athletic is something I'm delighted to do. It's a club with rich history and a brilliant, young squad that I can hopefully help progress up the league during my time here.
"It's a move that has been in the works for a little while and one that had to be right for myself after being at Newcastle for such a long time, but after speaking to the gaffer, who outlined his plans and where he sees the club going in the future, I was excited to sign and hopefully bring my experience to this journey."