If your are driving from Oviedo, take direction Bilbao and do not enter Santander, as you pass by El Astillero take Exit 8 towards Sarón / San Salvador / Astillero, and then take the right turn to Astillero passing a bridge over the river Solía. After passing the bridge you will find a roundabout and you need to take the exit marked in green as “Ria de Solía”, as described in the following map.