Porth Navas (also Port Navas) is a small village at the head of the west end of Port Navas Creek, part of the Helford River. It is located near Mawnan Smith and Falmouth in Cornwall, United Kingdom. It lies within the civil parish of Constantine. On 1 April 2009 all of Cornwall's District Councils were abolished and power centralised at County Hall in Truro: the new authority is known as Cornwall Council.
Porth Navas's prosperity -- for jobs, living and recreation -- depends on its once pristine beauty as part of the Helford River. A campaign group has been established in the Village to protect and preserve Port Navas Quay -- a Grade II site which has been visually spoiled and degraded.
The road from Mawnan Smith crosses the Trenarth Bridge which is at the head of another section of Port Navas Creek.