Beach town in October

October is probably a bit late in the season, but if the weather holds you can still enjoy the beaches and the crowds will be thin.
Most towns in the area are too commercial and overdeveloped for my taste.
I like Nerja a lot, it's a small town. Mijas Costa is nice too, and the old village of Mijas (a bit in the interior) is a must see.
If you want something more city like, you might like Fuengirola or Marbella. Malaga is a bit too big of a city for my ideal of a beach place.

I have enjoyed the beach on many parts of the Mediterranean in at least the first half of October, but Nerja is the only one I have visited in Spain. Shallow or secluded beaches that are normally popular for swimming retain plenty of warmth at that time. (The swimming standards of an American/Seattleite are different from those of Europeans who only head to the beach in August.) The part of the southern Spanish and Portuguese coast that is west of Gibraltar will be different, with more Atlantic influence.

Thanks for your replies! I was actually considering Nerja as our final decision for a coastal town, due to the positive info Ive read so far. My next question would be about travelling there. Initially, our route would take us from Madrid into Granada, then a coastal town like Nerja, followed by Sevilla and finally Barcelona. However it felt almost as if we were backtracking by doing this, especially when we start to consider train rides, etc. I was wondering if anyone had any suggestions to better route our destinations to make the most of our travel times as well as to leave as much time as possible for enjoying the actual towns themselves. Thanks again!

We went 'clockwise' the last week of Sept and first week of Oct: Flew into Barcelona > train to Madrid > train to Granada > rent car when leaving Granada and drove across to Arcos/Rhonda, with a side trip to swim at Tarifa and that great little beach just north called Valdevaqueros where the windsurfers are (great sleepy beach bar/restaurant there too....) We then drove into Sevilla and dropped the car > train back to Barcelona. First choice would have been to fly out of Sevilla, but I could not get the flights to work out without schedule risk.

Thanks for your reply! Since we want to finish off our trip with Barcelona we would be doing a complete reversal of your route lol! We went ahead and booked Nerja for a couple of nights, and we will be taking the bus from Granada there. Once we leave we will take a bus to Malaga, and catch the train to Seville.

Fly into international gateway Malaga, then bus to Nerja and on to Granada.
Your train journey then Granada-Sevilla-Cordoba-Madrid-Barcelona.
I think this is the most efficient routing.