During their early careers, the five ships served in II Battle Squadron, with "Preussen" its flagship. The fleet was occupied primarily with routine peacetime training and foreign visits. In 1912, "Braunschweig" was placed in reserve and she was joined the following year by "Elsass". "Lothringen" and "Hessen" were slated to be decommissioned in 1914, but the outbreak of World War I in July prevented this and they remained in service with the High Seas Fleet. They and "Preussen" took part in the fleet operations in the first two years of the war, while "Braunschweig" and "Elsass" went to the Baltic with IV Battle Squadron, where they eventually saw combat with the during the Battle of the Gulf of Riga in August 1915. "Hessen" took part in the Battle of Jutland in May 1916 and saw limited combat with British battlecruisers late in the battle. All five of the ships were withdrawn from service starting in 1916, thereafter being used in subsidiary roles, including as barracks and training ships.