"Ikoma" served in World War I, initially during the blockade of the German port of Tsingtao in China during the Battle of Tsingtao from September 1914 as part of Japan's contribution to the Allied war effort under the Anglo-Japanese Alliance. After the fall of the city, "Tsukuba" was sent out as part of the search for the German East Asiatic Squadron in the South Pacific until the destruction of the German squadron in the Battle of the Falklands in December 1914. From 1 November 1914 to 17 January 1915, "Ikoma" was based out of Hong Kong, Singapore and Townsville, Australia, protecting British colonies and shipping from German commerce raiders.