1914, Yakumo was deployed to Singapore preparatory to searching for the German commerce raider , but the ship was sunk before the mission began. Yakumo served as the flagship of Destroyer Squadron (Suiraisentai) 2 from 13 December 1915 to 1 December 1916 and then of Suiraisentai 1 from 1 to 12 December. In February 1917, the ship began patrolling the South Pacific and Indian Oceans, searching for German commerce raiders. She began the first of her many training cruises on 5 April when she departed for North America and Hawaii, before arriving back in Japan on 17 August. In October 1918, Kichisaburō Nomura was appointed captain of Yakumo for two months, only one of which he spent on board the vessel, as a political appointment to qualify Nomura for flag rank. Interwar years On 1 September 1921, Yakumo was re-designated as a 1st class coast-defense ship and used primarily for training duties in long-distance oceanic navigation and officer training for cadets in the Imperial Japanese Navy Academy. In this capacity, she participated in 13 more voyages in the 1920s and 1930s to Europe, North and South America, and the South Pacific, including a circumnavigation of the globe from August 1921 to April 1922, in company with the armored cruiser . Two of the naval cadets that participated in this cruise were Princes Kuni Asaakira and Kachō Hirotada. In 1924, four of Yakumos 12-pounder guns were removed, as were all of her QF 2.5-pounder guns, and a single 8 cm/40 3rd Year Type anti-aircraft gun was added. In addition three of her torpedo tubes were removed. Three years later, her boilers were replaced by six Yarrow boilers, formerly from the battleship , which reduced her power to and maximum speed to . These boilers used a mix of coal and fuel oil, and the ship now carried a total of of coal and of oil. During a visit to Tsingtao in 1932, Yakumo and Izumo had to land marines on 13 January to quell a riot by Japanese residents there. The following year, the ship was reclassified as a training ship. On 6 November 1936, between the islands of Saipan and Truk, an accidental explosion in her front magazine killed four crewmen and flooded her front food locker. Repairs were made underway and Yakumo arrived home two weeks later. A month after her return, in December 1936, Captain Matome Ugaki assumed