Carmarthen railway station is on the West Wales Line serving the town of Carmarthen, Wales, south of the River Towy, 245 miles 55 chains (395.4 km) from the zero point at London Paddington, measured via Stroud. The station is operated by Transport for Wales. Great Western Railway also run a limited service between Carmarthen and London Paddington, usually six trains each way daily with an additional return service to Bristol Parkway.

The West Wales lines are a group of railway lines from Swansea through Carmarthenshire to Pembrokeshire, West Wales. The main part runs from Swansea to Carmarthen and Whitland, where it becomes three branches to Fishguard, Milford Haven and Pembroke Dock.