'RU' was the designation of Allied convoys (together with a numerical suffix) plying the route from Reykjavik, Iceland, to Loch Ewe or, in the case of the last four, Belfast Lough, UK, and as such reciprocals of the 'UR' series (December 1941/May 1945).

The first of the 168 such convoys was RU.1 of 20/25 December 1941 with the 395-ton Dutch Amstelstroom, 1,832-ton Norwegian Bollsta, 1,066-ton Polish Hel, 1,512-ton British Hindsholm, 1,274-ton British Knut, 3,489-ton Norwegian Norse Lady, 1,345-ton British Skjold and 5,627-ton British War Sudra. The last was RU.163 of 22/27 May 1945 with the 2,847-ton British Empire Elgar, 1,209-ton Icelandic Katla, 2,144-ton Norwegian Mui Hock, 1,335-ton British Norco, 986-ton British Rother and 2,001-ton Panamanian Yemasee.