The average train between Slough and Carmarthen takes 4h 40m and the fastest train takes 3h 52m. There is a train service every few hours from Slough to Carmarthen. The journey time may be longer on weekends and holidays; use the search form on this page to search for a specific travel date.
Trains run hourly between Slough and Carmarthen. The earliest departure is at 6:39 AM in the morning, and the last departure from Slough is at 10:54 PM which arrives into Carmarthen at 7:42 AM. All services require a transfer at Reading and take an average of 4h 40m. The schedules shown below are for the next available departures.


3h 52m • 2 changes


4h 14m • 2 changes


4h 3m • 2 changes


4h 11m • 2 changes


3h 52m • 2 changes


4h 14m • 2 changes


4h 3m • 2 changes


4h 11m • 2 changes


3h 52m • 2 changes


4h 14m • 2 changes


4h 3m • 2 changes


4h 11m • 2 changes
Want to know about travelling from Slough to Carmarthen? We have put together a list of the most frequently asked questions from our users such as: What is the cheapest mode of transport? What is the quickest option? How much do tickets usually cost? and many more.
No, there is no direct train from Slough to Carmarthen. However, there are services departing from Slough station and arriving at Carmarthen station via Cardiff Central. The journey, including transfers, takes approximately 4h 40m.
Slough to Carmarthen train services, operated by Great Western Railway (GWR), depart from Reading station.
Slough to Carmarthen train services, operated by Great Western Railway (GWR), arrive at Carmarthen station.
Book your Slough to Carmarthen train tickets online with Great Western Railway (GWR), Transport for Wales and Elizabeth Line (TfL).
The distance between Slough and Carmarthen is 258.6 km. The road distance is 327 km.
You can take a train from Slough to Carmarthen via Reading and Cardiff Central in around 4h 37m.