From Portugal:

You enter Spain through Tui. From Tui you reach Pontevedra through the A-55 and the N-550. From Vigo, directly through the A-9, or through the N-552 up to Redondela, where you take the N-550. In Pontevedra you take the road to Beiramar (PO-12), accessible from the highway and also from the N-550. Marín is found in the south area, at a short distance of 8 km through this road.