Completed in April 1927 as Biscaya for John T. Essberger, Hamburg. In August 1939 interned at Las Palmas while en route from Hamburg to Port Arthur, Texas. On 7 Oct 1939, left to return to Germany but was intercepted and captured on 19 October by HMS Scotstoun (Capt S.K. Smyth, RN) on Northern Patrol in the Denmark Strait in 66°30N/23°00W. The ship was taken to Leith by a prize crew (LtCdr R.H.A. Clark, RNR) and renamed Empire Unity by Ministry of War Transport (MoWT).

Post-war:
In 1947 renamed Stordale for Storship Transports Ltd, London. 1951 sold to Greece and renamed Mageolia for Mageolia Naviera (T. Pappadrinitriou), Panama. After October 1963 used as static bulk oil storage vessel at Piræus and Kythira. In April 1966 broken up at Burriana, Spain.

At 01.05 hours on 5 May 1945 U-979 fired a spread of three torpedoes at convoy RU-161 and hit the Empire Unity 14 miles west-northwest of Akranes, Iceland. The tanker was struck on the starboard side by two torpedoes, causing the flooding of six tanks. The crew initially abandoned ship, but most soon reboarded the damaged vessel after she was brought to Hvalfjordur by HMS Northern Spray (FY 129). 12 survivors were picked up by HMS Northern Sky (4.41) and taken to Belfast.

On 20 June 1945 the Empire Unity left Reykjavik under tow after temporary repairs and arrived five days later in Methil for permanent repairs.