'HK' was the designation of Allied convoys (together with a numerical suffix) plying the route from Galveston, Texas, or Pilottown, Mississippi, to Key West, Florida, and as such reciprocals of the 'KH' series (September 1942/May 1945).

The first of 183 such convoys was HK.100 of 4/8 September 1942 with 33 merchant vessels and five escorts (converted yacht Carnelian, submarine chasers SC-500 and SC-508, and auxiliary motor minesweepers YMS-62 and YMS 64), and the last was HK.373 of 10/12 May 1945 with two merchant vessels and no escorts.