Cantabria is a region of Spain, located on the northern coast. Its main infrastructure hub is Santander with about 180,000 inhabitants.
Cantabria has the following sub-regions:
The best airport is in Santander. Since it is a small airport international flights might go to Bilbao. Bilbao is only 100km (60m) from Santander.
Arrival by ferry from UK is also possible in Santander. There is a ferry terminal.
Arrival by car from Bilbao is via the A8 freeway.
Since many interesting places are outside the main city Santander in small villages in the country side a car is recommendable. Alternatively public buses are available to larger towns. Frequent public buses are available between Santander and Bilbao.
If you are coming from the Basque Country the logical continuation is to go to Asturias. Just follow the coastline westwards.