Are parts of the coast of Northern Spain remote and desolate, or is the entire coastline heavily visited?

Could anyone tell me whether the coast of Northern Spain (Galicia, Asturias, Cantabria, Euskadi/Basque Country) has any remote stretches with no cities or towns, where one would probably not find any other people, throughout the year?

Some sources suggest that there are long, remote, generally empty stetches of coastline (especially farther west), but other people have told me that there are towns pretty much along the whole length, while still others have told me that there are long stretches with no towns, but that at least during the month of August even the most remote of these are filled with a fair amount of people.

It would be ESPECIALLY helpful if someone could tell me whether the more secluded stretches could be compared with any specific part of the Northern California coastline, in terms of remoteness and lack of people.

Thanks, amigos!