Austin has passed a medical at Saltergate and will officially become a Spireite on 1 July when his current Swans deal expires.
Austin had agreed a new one year deal at the Swans following his appearances last season but Chesterfield have come in with a two year deal which Kev has accepted and feels his chances of appearances are increased greatly with the move.
"He has been a fantastic servant for this club,'' explained Roberto via the official web site. "Although we could have kept him for another year, we felt the least he deserved as a reward for his loyalty, service and effort was the chance of securing himself a two-year deal.
"He has played a massive role for this football club and been a rock in the dressing room.
"Kevin is the ultimate professional and I'm sure he has more than two good years left in him at Football League level.
"Everyone at the club would like to thank him for his services and wish him well for the future. I'm sure the fans would go along with that as well.
"He will certainly a big asset for Chesterfield.''
"I couldn't have asked for any more over those four years and I'm obviously sad to be leaving the club,'' explained Austin via the same medium. "But life goes on and I'm looking forward to the new challenge at Chesterfield
"When I signed for the club four years ago I never expected it to turn out the way it did. Obviously at 31 I felt was coming to the end of my career and I left Bristol Rovers for Swansea hoping to taste a bit of success.
"But to experience two promotions, two trips to the Millennium Stadium and success in the FAW Premier Cup was beyond my wildest dreams.
"I will leave Swansea with some great memories of the club and the fans. But I still feel in good nick and I am not ready to hang up my boots just yet.
"Hopefully I can enjoy some more success at Chesterfield.''
All the best Kev and thanks for the service