'BN' (iii) was the designation of Allied convoys (together with a numerical suffix) plying the route from Cape Gloucester, New Britain, to Langemak Bay, New Guinea, or Guadalcanal, and as such reciprocals of the 'NB' series (April/June 1944).

The first of these five convoys was BN.16 of 13/14 April 1944 with the 7,176-ton US Augustus Thomas escorted by the US submarine chaser PC-1132, and the last was BN.31 of 27/29 June 1944 with the 7,207-ton US Henry L. Gantt and 7,176-ton US Thomas W. Symons escorted by the US submarine chaser SC-981.