SS Harpalion was a British cargo steamship. She was built in 1910 for J&C Harrison of London, and sunk by a U-boat in 1915. She is one of at least three cargo ships to have borne the name Harpalion from Greek mythology. J&C Harrison had a later steamship of the same name that was built in 1932 and sunk in 1942. The National Steamship Co had a motor ship of the same name that was built in 1947 and scrapped in 1979.
In 1910 and 1911, William Gray and Company of West Hartlepool, County Durham, built three sister ships for J&C Harrison. Yard number 771 was launched in April 1910 as Harpagus, and completed that June. Yard number 779 was launched on 4 October 1910 as Harpalion, and completed that November. Yard number 789 was launched in May 1911 as Harpalyce, and completed that June.
Harpalions registered length was , her beam was , and her depth was . Her tonnages were and . She had a single screw, driven by a three-cylinder triple expansion engine made by the Central Marine Engine Works in West Hartlepool. It was rated at 574 NHP, and gave her a speed of .
J&C Harrison registered Harpalion at London. Her UK official number was 129152, and her code letters were HRWF.
In February 1915, Harpalion left London in ballast for Cape Henry, Virginia. On 24 February she steaming west in the English Channel, when torpedoed her, west of the Royal Sovereign lightship. The explosion burst one of the boilers in her stokehold, killing three of her Chinese stokers, and badly scalding her third engineer.
Harpalion did not immediately sink, and various merchant ships and warships sighted her. A tugboat from Le Havre to take her in tow, but Harpalion sank shortly after the tug reached her. All of Harpalions surviving crew were rescued, and her third engineer was hospitalised at Newhaven.