 Recalled to Germany in 1914, "Bremen" was decommissioned in March and overhauled, which included replacing four of her 10.5 cm guns with a pair of guns.This work was still being done when World War I broke out that year, and upon completion of her modernization in May 1915, "Bremen" was assigned to the naval force in the Baltic Sea.She took part in several patrols in the eastern and northern Baltic to search for Russian warships, but she saw no action.