The Yalmy River rises in a valley in a remote alpine wilderness area that forms the boundary between the Snowy River National Park and the Yalmy State Forest, and flows generally south, then west, then south, then south by west, joined by three minor tributaries, before reaching its confluence with the Rodger River east of Hicks camp site within the national park in the Shire of East Gippsland. The river descends 315 metres (1,033 ft) over its 28-kilometre (17 mi) course.[2]
The entire course of the river is contained within, or forms the eastern boundary of the Snowy River National Park.[2]