If you drive or walk along Via Aicastello (street map here) keep your eyes open for paths that lead from the sidewalk down onto the rocks. Any of these are potential free spots for laying out on the rocks and taking a dip in the refreshing water. This spot is a real favorite among the locales. From the road, next to the Lido Bellatrix, there is a small path that will lead you down to a staircase and some easy to walk on boulders that provide a secluded spot for a swim. Find a smooth rock to spread your towel on and watch the locals to see the best way to get in and out of the water.