Serapo is Gaeta's main beach and one of the best on the Lazio coast: a wide crescent of golden sand sheltered by the peninsula to one side and backed by the lower town on the other. The water is clear and relatively shallow near the shore, making it suitable for families. In the height of summer the beach is solidly packed with umbrella-and-lounger concessions, but the public sections remain free.
The beach curves for around 800 metres and faces west, so it catches the late afternoon sun. Behind it, the lower town's promenade is lined with gelaterie, restaurants, and the kind of seafront bars that come alive after 9pm in August.
Arrive early in July and August if you want a spot. Outside peak season — May, June, and September — the beach is dramatically less crowded and swimming is still perfectly viable.