'CZ' was the designation of Allied convoys (together with a numerical suffix) plying the route from Curaçao, Netherlands West Indies, to Cristóbal at the eastern end of the Panama Canal, and as such reciprocals of the 'ZC' series (September 1942/February 1943).

The first of this 'Curaçao to Panama Canal Zone' series was CZ.1 of 26/30 September 1942 with eight tankers (7,698-ton US Esso Bayonne, 8,916-ton US Gulfcrest, 7,141-ton US Gulfdisc, 6,257-ton US Hadnot, 12,590-ton US John D. Archbold, 7,027-ton US Meton, 8,129-ton Norwegian Norfjell and 6,950-ton US Thomas H. Wheeler), and the last was CZ.10 of 2/5 February 1943 with the 9,003-ton US tanker F. Q. Barstow.