The Wa River (Thai: ลำน้ำว้า) is a river of the Thai highlands in Thailand, a tributary of the Nan River, part of the Chao Phraya River basin. It has its source beneath 1,745-metre (5,725 ft) high Doi Phi Pan Nam mountain of the Luang Prabang Range and joins the Nan River near Wiang Sa town in Wiang Sa District, Nan Province.The Wa River is a popular river for white water rafting.