Santillana del Mar is 30 kilometres west of Santander along the A-67 motorway and N-611 road. There is no train station; the nearest rail connection is at Santander, which has services to Madrid (about 4 hours 30 minutes) and connections to Bilbao and the Basque coast.
Regular buses run from Santander bus station to Santillana del Mar throughout the day, operated by Autobuses Palomera. The journey takes about 45 minutes. Santander itself is served by ferry from Plymouth and Portsmouth (Brittany Ferries), which makes this a realistic option for travellers bringing a car from the UK.
If you are driving, parking in the historic centre is restricted; there are signed car parks on the edge of town and a short walk brings you to the pedestrian streets.