When you climb the Acropolis, you realize Athens is quite close to the sea. It only takes a tram or bus ride to reach the coast, which is dotted with both public and private beaches. Mind you, they're nothing like the ones on the islands, but if you can't wait, Athens' beaches make a nice side trip from the dust and heat in downtown. A thumb of rule, the further you get from Athens, the nicer the beaches, and the private beaches are definitely better than the scruffy, but free, public ones. But all of them are good for people watching.