Moratuwa is a large municipality located on the southwestern coast of Sri Lanka. It is situated along the Galle–Colombo main highway, approximately 18 km (11 mi) south of the center of Colombo, near Dehiwala-Mount Lavinia.
The city is characterized by its geography, as it is surrounded on three sides by water. It borders the Indian Ocean to the west, Lake Bolgoda to the east, and the Moratu River to the south. According to the 2012 census, the suburb had a population of 168,280.