This route follows the entire life of the River Tawe, from the mouth at Swansea Bay to the first trickle in the high, exposed uplands below Llyn y Fan Fawr in Bannau Brycheiniog.
Specifically:
- Lower section: the Tawe starts in areas defined by a port, followed by historical coal, metalworking, and transport industry
- Middle section: the route follows the Tawe through the upper Swansea Valley, passing limestone geology, glacially shaped landscapes, and tributaries such as the Afon Haffes, alongside settlements that developed around agriculture, quarrying, and later industrial activity linked to the river
- Upper section: here, the river rises in exposed upland terrain beneath the Black Mountain, emerging from peat and grassland as a small but continuous watercourse in an area shaped by early pastoral use and long-established upland routes
