Cardiff is well connected by rail from London Paddington — the journey takes about two hours on the fast service, with trains running roughly every 30 minutes. This is by far the easiest way to arrive from London. Cardiff Central station is right in the city centre.
By road, the M4 motorway runs directly into Cardiff from London and Bristol; the Severn Bridge crossing (the M48) is now toll-free. From the north, the A470 brings you down through the valleys from Merthyr and beyond.
Cardiff Airport handles mainly short-haul European routes and some transatlantic services. It sits about 20 kilometres southwest of the city and is connected by dedicated bus to Cardiff Central. If arriving from further afield, Bristol Airport is larger and better connected, with an easy bus link to Cardiff.