It is an elongated estuary in the extreme southeast of Cox's Bazar district dividing the district from Arakan, Myanmar. It rises in the Arakan hills on the southeastern borders of the district and flows into the Bay of Bengal. Its width varies from 1.61 km to 3.22 km. The river is influenced by tide. Sittwe in Myanmar is on the eastern bank and Teknaf upazila of Cox's Bazar district is on the western bank of the river.
The Naf River's average depth is and maximum depth is .
Historically, Shapuree island located at the mouth of the river, plays important role and considered as one of the immediate causes for the first Anglo-Burmese War.