Surfing in Northern Spain

Hey there. I am studying abroad in Spain next spring. My homebase is in Santander, but I am wanting to travel to Bilbao and San Sebastian and some other places to catch some surf. I am thinking about just buying a board once I get over there then selling it back but I didn't know about travel. I am not going to have a car, so what is the best way to get around??
Thanks
Thanks