A shorter period of dockyard work took place from 7December to 27 January 1908. She returned to the fleet for the normal peacetime routine of training exercises, and after the conclusion of the autumn maneuvers, "Kaiser Wilhelm der Grosse" was decommissioned in Kiel on 21 September. She was taken into the "Kaiserliche Werft" shipyard in Kiel for an extensive modernization that lasted until 1910. During the refit, four of the ship's 15 cm guns and the stern-mounted torpedo tube were removed. Two 8.8 cm guns were added and the arrangement of the 8.8 cm battery was modified. Her superstructure was also cut down to reduce the ship's tendency to roll excessively, and the ship's funnels were lengthened. After reconstruction, the ship was assigned to the Reserve Division in the Baltic, along with her sister ships. She was reactivated on 31 July 1911 and assigned to III Squadron during the annual fleet exercises, then returned on 15 September to the Reserve Division. She remained there for the rest of her peacetime career.