San Felice Circeo's pleasures divide between the coast and the mountain. On the coast, the beaches along the Baia di Quarto Caldo and toward Sabaudia are excellent: long, sandy, and relatively uncrowded compared to points further north. The sea caves below Monte Circeo — accessible by boat from the harbour — are the other distinctive draw, especially Grotta delle Capre and Grotta dell'Impiso, both cut into the sea cliffs and requiring a local boat to reach.
On the mountain, the Circeo National Park has well-marked trails through holm oak forest up to the summit ridge of Monte Circeo, with views that take in the Pontine Islands, the Pontine Plain, and — on clear days — south toward Naples. The combination of accessible beach, serious walking, and genuine prehistoric and mythological associations makes this a more interesting stop than most of the Lazio coast.