Ponza isle, Pontine Islands archipelago: The Pontine Islands lie in the Tyrrhenian Sea to the west of Naples. They comprise Ponza, the main island, along with Palmarola, Zannone and Gavi, plus Ventotene and Santo Stefano to the southeast, closer to the mainland. Stunning natural scenery, secluded beaches and island chic make these popular but unspoilt tourist spots.