If you have a hire car and are coming to San Sebastian for more than a day, park your car for free at one of the car parks off Avenida de tolosa next to the University (to the west of the city centre) and get the 5 or 25 Donostia Bus service into town (€1.20 /single). Otherwise 24hr underground garages in the centre cost about €13/day and there is no long term street parking anywhere near the city centre.
Universidad del Pais Vasco, Avenida de Tolosa, San Sebastian-Donostia
Updates
This is a fantastic place to park. We recently drove our car to San Sebastian and the parking and traffic were awful. Checked online and found this article, it was the perfect place to park. The bus that we got was the 33, you can also catch the 40 into town as well
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