Hammamet is all about beaches. The best stretches northwest from the medina. Dotted by private hotel areas, it has plenty of public bits, and water sports facilities at regular intervals. There's a lovely stretch outside the International Cultural Centre. If you have your own transport, you can drive out beyond Yasmine - after the buildings stop, the beach is empty and wild, and seems to go on forever.
The beach running towards Nabeul is also well worth spreading your towel on.
