The 32-year old defender had rejected fresh terms to stay at previous club Bolton Wanderers for whom he made 32 appearances last season following a move from Sunderland.
Ex-Sheffield Wednesday and Chelsea stopper Thome has had a flurry of top flight experience since arriving in England back in 1998 and will hook up once again with his former Wanderers team mate Per Frandsen at the JJB Stadium.
"I'm really pleased to get my future sorted out and I'm delighted to sign for Wigan Athletic after the interest they have shown in me. I can't wait to get started now and am already looking forward to my first training session with my new team-mates on Thursday morning" Thome told Wigan's Official Site