Let KAYAK do the searching
Based on KAYAK hotel searches, the most popular destination is Castro-Urdiales (43% of total searches to Cantabria). The next most popular destinations are Santander (29%) and Santillana del Mar (14%). Searches for hotels in Miengo (14%) are also popular.
KAYAK users have found double rooms in Cantabria for as cheap as $44 (Santander) in the last 3 days. The average price is $266.