The Austrian joined the 'Potters' from Tottenham for a fee in the region of £18m in August of last year, but struggled to produce his best form as Stoke slipped through the Premier Legaue trapdoor.
The 25-year-old played just 19 games for Stoke, failing to make a single appearance after the arrival of Paul Lambert in January.
Wimmer is currently on international duty with his country, but will report directly for pre-season with the side that finished 13th in the Bundelsiga last season.
The loan deal includes an option for Hannover to make the deal permanent.
May 27, 2018