Hirado and Yahagi were in the Allied 2nd Southern Squadron led by the battleship Satsuma and commanded by Rear-Admiral Matsumura Tatsuo, patrolling the region around Sumatra unsuccessfully for the German cruiser Emden.

On 7 February 1917 the Imperial Japanese Navy formed the First Special Squadron which composed the cruisers Yahagi, Tsushima, Suma and Niitaka, together with the Second Destroyer Flotilla.

On 26 March 1917, the British Admiralty further requested the deployment of Chikuma and Hirado to Australia and New Zealand to protect shipping against German commerce raiding operations.

Yahagi and Suma were ordered to the Indian Ocean to continue cooperation with the British China Squadron, and Tsushima and Niitaka proceeded to Mauritius.

After the end of the war, Yahagi was assigned to patrol off the coast of eastern Russia to provide protection and support for supply convoys to Japanese ground forces in Siberia during Japan's Siberian Intervention against the Bolshevik Red Army.

Stricken from the navy list on 1 April 1940 and re-designated Hai Kan No.12 at the Etajima Imperial Japanese Naval Academy, she served as a barracks ship for submarine crews until 1943.