'GK' was the designation of Allied convoys (together with a numerical suffix) plying from Guantánamo, Cuba, to Key West, Florida, and as such reciprocals of the 'KG' series (September 1942/May 1945).

The first of these 163 convoys was GK.700 of 1/5 September 1942 with the 4,980-ton Norwegian Anna Odland, 1,535-ton US Bacoi, 4,116-ton Norwegian Fernhill, 3,362-ton Honduran Gatun, 2,283-ton Honduran Merida, 4,426-ton Polish Paderewski, 2,638-ton Panamanian Portland, 6,625-ton US Robert E. Hoskins, 7,176-ton US Robert Gray, 6,032-ton US Thomas P. Beal, 1,712-ton Dutch Tiberias and 2,226-ton Panamanian Vagrant. The last of the convoys was GK.877 of 3/6 May 1945 with the 4,480-ton Panamanian Manuel.