https://www.icmat.es/facilities/howtoarrive
If your accommodation is in “La Residencia de Estudiantes”
It is a hotel situated inside the CSIC (Spanish Research Council). There are two entrances (C/ Pinar 21 and C/ Serrano 113-117 (The entrance of the CSIC)). If you arrive after 22:00 you have to call to the inter phone. Below a map is attached.
There are several ways to go to the hotel from the airport.
During the school we have hired a bus which will take you every morning (at 9:00 from Monday to Friday) from the bus stop on Serrano 111 to the ICMAT and in the evening from the ICMAT to the hotel.
If your accommodation is at IES Hotel Escuela
To get there from the airport you have, for example, the following option:
The hotel is about 1 minute walking distance from the bus stop.
During the school we have hired a bus which will take you every morning (at 9:40 from Monday to Friday) from the hotel to the ICMAT and in the evening from the ICMAT to the hotel.
If your accommodation is at RESA
This a residence situated on the campus in 7 minutes walking distance from the Math. Institute (www.icmat.es) The rooms are very comfortable and there is a kitchen in each room. The main disadvantage is that this place is not in the city center (about 20 minutes by local train see http://www.renfe.com/viajeros/cercanias/madrid/index.html and choose "Cantoblanco Universidad - Sol" for timetables).