The Switzerland international is ecstatic about taking on a new challenge at the Hessian outfit this season after S04's new arrivals reduced his chances of a starting berth
The arrivals of Kevin-Prince Boateng and Christian Clemens have lowered the Swiss winger's chances of making regular appearances at Veltins Arena.
The 28-year-old is now relishing the opportunity of making an impact at Armin Veh's side, who recently qualified for the Europa League group stages.
"I'm delighted that the deal went through and about getting to know the city and the team," Barnetta told the club's official website.
"First, I must meet with the national team, however, and will return to Frankfurt with Pirmin Schwegler in 10 days."
Barnetta has scored 10 goals during 68 appearances for his country to date.