'ONM' (i) was the designation of Allied convoys (with a numerical suffix) plying the route between Milford Haven, Wales, and Belfast Lough, Northern Ireland (July 1941/January 1943).

The first of these 27 convoys was ONM.1 of 25/26 July 1941, and the last was ONM.162 with only the 7,174-ton Ocean Vestal.