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Tywi Source Sea

The River Tywi is Wales’ longest river, coming in at 75 miles long. It weaves its way from the source in the Cambrian Mountains to the sea at Carmarthen Bay. Flowing through the sharp hills of the Tywi Forest, it creates a boundary between Ceredigion and Powys. The gentle river also passes through the towns of Llandovery and Llandeilo before entering the Irish Sea in a broad estuary between Llanstephan and Ferryside.


The Tywi river


The Tywi is known across the nation for being home to large sea trout. These fish enter the river each spring and early summer to breed, and live among brown trout, eels, pike and a variety of other small fish species. The river also has a thriving population of otters, and grey seals are common in the lower reaches. Other wildlife such as red deer, badgers, foxes and migratory birds have been spotted along the river.

Ramble along the River Tywi and explore the undisturbed wilderness for yourself, stopping at local hotels or Airbnbs along the way. Follow the water down to the sea, before enjoying the local pubs and tearooms for a well-earned break.


A otter sitting on a rock in the Welsh countryside


Before you visit the Tywi valley, check out our resources and guides that are helpful for first-time visitors to Wales and seasoned tourists. Our local tips and insider information make your journey all the more enjoyable. From the rugged hills of the Tywi forest to the flat plains of the flat estuary, you’ll be able to make the most of your River Tywi walk from source to sea.