'CB' was the designation of Allied convoys (together with a numerical suffix) plying the route from Durban, South Africa, to Beira, Portuguese East Africa and beyond, and as such reciprocals of the 'BC' series (July 1943/August 1944).

The series began with CB.1 of 26 July/6 August from Durban, South Africa, to Kilindini, Kenya, with the 7,323-ton British City of Oran (crippled by Korvettenkapitän Eitel-Friedrich Kentrat’s U-196 on 3 August and sent to the bottom by an Allied warship), 6,054-ton British Delane, 6,921-ton Brtish Empire Stanley, 5,132-ton Dutch Hoogkerk, 4,164-ton Greek Irene S. Embiricos, 8,988-ton British Narbada, 9,142-ton British PortMelbourne and 5,996-ton British Tactician. The last was CB.8 of 4/16 August 1944 from Durban to Kilindini with the 8,249-ton Dutch Macuba and 4,329-ton Egyptian Star of Alexandria.