"Isonami" was launched at Maizuru Naval Arsenal on 21 November 1908 and completed on 2 April 1909. The ship saw service in World War I and the Siberian Expediation. She was converted into a minesweeper on 1 December 1924 and was renamed "W-7" on 1 August 1928. The ship was decommissioned on 1 June 1930, but she continued in service as a tugboat and a dispatch boat until 9 April 1935. Afterwards she became a floating pier at Kure Naval Arsenal.