I went to Camping Fuente del Gallo on a vacation a few years ago in Cadiz, a place I escape to to swim in the beaches and coves. This site is pretty good as it is clean and has plenty of shade. There's a pool if you tire of the salt water. One drawback to this is a bit far from town so you need a car to get around. Like any local campsite, there are day trip options to Gibraltar, Tanger, the white villages of Cadiz, or whale and dolphin watching. There are also bike paths, boat trips, etc. Oh and do not forget to visit Canos de Meca, nearby town with a good atmosphere.