First of all, I would like to point out that there are two Paradores in Santillana del Mar. The one I’m referring to is the three-star Parador (the other one is a four-star hotel named Parador Gil Blas).
We stayed there one night, and we may say it was a wonderful experience. The hotel had a warm, rural style which made us feel like home from the very moment we arrived. The room was perfect, very spacious, full of light coming from the old style window, with a great view of the garden. The bathroom, wardrobe and beds were just perfect. Staff members were very helpful.
The town is gorgeous to spend some hours, preferably during night hours when tourists give space to the calm and quiet as if you were going back in time. That’s why a night in the Parador is well worth!
If you’re going by car don’t forget to have a printed copy of your reservation because it will be very useful in order to be able to park in front of the hotel (there’s a police-officer who impedes road traffic to access the historical part).

After reading the "dreadful" comments here below we wondered what was going to be our miserable fate at the Parador Gil Blas at Santillana del Mar where we had booked 4 nights.
First we found immediately the entrance to the historic centre where we were halted by a policeman. It was fiesta de Santa Juliana, streets were cut off for cars but by miracle the policeman spoke French and kindly showed us the shortest way to reach the Parador and its private parking.
We did not expect a porter to take our luggage because most 4 stars hotels have no porter anymore! The receptionist did understand and speak some English and took our luggage to our room (maybe the Parador management had read the complaint here below!).
Nearly all persons at the reception did understand and speak some English; one would also understand some French. They were correct, some were kind.
We had booked a double room with "salon" at the "dias doradas" rate (for persons over 60 yr.) of 170,56 €/night breakfast and tax incl. The room was in fact an apartment of nearly 60 m2.
Remarkable was the old wooden floor. The room was somewhat dark, stronger light bulbs would be welcome; maybe it is done on purpose to keep the medieval atmosphere. Nights were very quiet.
The room was quite clean, the bath room large and complete. Room service without defects.
We tested the service by complaining about the noise made when opening the door to our room. The same afternoon the hinges of all our room doors had been lubricated.

Breakfast was up to the usual standards of a 4 star hotel in Spain. There was a nice choice of Cantabrian cheeses. The waitress was efficient and kind. She spoke only Spanish but we know enough Spanish to say good morning and order coffee with milk.
We had no diner at the Parador.
From experience we know that when there are many foreign tourists in a Parador they all enter the restaurant at the opening time what results in congestion and slow service. We usually prefer the ambiance of the local restaurants. There at the opening we are the only ones and get full attention as the Spanish customers arrive later, around 10 p.m.
In Santillana we would recommend the restaurant Casa Cossio, near the church, superb "parilla's" (grilled on barbecue) of tasteful meat. The pork ribs are the speciality. The menu is translated in English, French and German. Waitresses are efficient but speak only Spanish.
Tourists may complain that Spaniards are not very clever on foreign languages but, quite frankly, do they speak Spanish in restaurants in the U.K.? I made a trial, for the fun, speaking French in hotels and restaurants in London; result 1/10.

Just one thing about Cantabria. The country, the mountains, the sea side are very nice but don't expect sunshine. When the Spaniards are fed up with sun and hot weather they go on vacation in … Cantabria!

This was classed as a 4 star hotel on the Paradores website so, as we originally intended to spend all our holiday using Paradores, we booked this one. What a dreadful experience. We had to telephone for directions to find the place and the receptionist wasn't at all helpful either time. Fair enough I don't speak Spanish but you would think staff would be used to English speaking guests. Our welcome was non-existent and, once again, no porter is available for luggage - a do it yourself job again. The reception staff seem to regard guests as a complete nuisance. The room was fine but SO DARK even with sunshine outside. We had a room with lounge and bedroom and the only way I could read, even in daytime, was by moving a small standard lamp around between the lounge and bedroom. Hotel was clean.
Dinner was a fiasco. We tried to book for 9pm as in the information guide it was from 8.30-10.30pm. The receptionist pointed told us 8.30pm or else so we arrived in the dining room at 8.30pm to be met by nobody! The room was full of British guests and when the head waiter eventually arrived he looked so out of his depth that all he did was wipe his brow then shout to a waitress to make a table ready for us. The service was efficient but unfriendly. None of the staff spoke English so take a dictionary. (Mine never left my side all the holiday as few speak English in north Spain). The wine wasn't even served in an ice bucket, just dumped on the table and the final insult was my fish was RAW. It was eventually taken back to be cooked but my partner's meal wasn't taken to be kept warm and obviously he was finished long before myself. When the fish was returned it was lovely but the whole meal was such a disaster we left the dining room then. Also, during the meal, I was sitting looking at packets of breakfast cereal etc, obviously all prepared for breakfasts. This hotel is NOT cheap (room only was 170 euros). There is nothing to do in Santillana except wander around joining the endless crowds of tourists who visit the village. Tatty gift shops abound. Like all Paradors they close up at 11.30pm so be warned. Would never return and this experience made us cancel all other Parador bookings we made and return to the wonderful Hotel Real, Sardinero, Santander. Same price but such a difference.......another world.