Seeing Marettimo's full complement of coves and grottoes from the sea is a must. While it's theoretically possible to rent your own small motorboat at Marettimo's port, your best bet for getting to know the 19km (12-mile) perimeter of the island is to have a local boatman take you on a giro dell'isola (island-circumnavigation) tour, which departs from either Scalo Nuovo, the "new port" where the hydrofoils dock, on the south side of town, or Scalo Vecchio, the "old port" where the island's fishermen are based, on the north side of town. You'll go counterclockwise around the whole island into the most beautiful and interesting inlets and sea caves. As long as the weather is warm, at least two stops for swimming are included. Note: Much of the island's coast is Nature Reserve, but locals have permits that allow their boats to get closer to certain areas than your rented motorboat could.
Excursions can be arranged ad-hoc at the harbor, whether with young men in designer T-shirts or salty old fishermen who'll shove aside their nets to make room for passengers. Many of these skippers have great stories to tell, and a few speak excellent English: Pietro Guerra (Scalo Nuovo; tel. 0923/923046; www.marettimotour.it), who captains the Nardina G. Alaska, spent many years in Alaska as a salmon fisherman before transporting his beloved Nardina G. back (via container ship and the Panama Canal) for service as a tourist excursion boat. Medi@tour (tel. 0923/923196 or 339/7729404; www.marettimoweb.it) has four boats that accommodate 7 to 16 passengers. Expect to pay 15€ per person for the round-island itinerary (3 hr. total, with stops for swimming) to 20€ per person for a more extended, 5-hour tour with longer breaks in the swimming coves.
Heading north from town, first up is the celebrated Grotta del Cammello. The roof has fallen in a cavern of limestone, creating gorgeous light effects and water colors that range from emerald to deep cobalt. On the northern side of Punta Troia is Grotta del Tuono, Cave of Thunder, for the sound that the pounding waves make when the mistral wind blows. A bit farther along is the Grotta della Pipa, named for a pipe-shaped rock here; then, around the promontory of Punta Mugnone, the south-facing inlet, Cala Bianca, is one of the most spectacular places for a swim on Marettimo. The white sea bottom creates a natural swimming pool, edged by high walls of karstic limestone. Next is the Barranche, those massive monoliths of limestone that create the amazing impression of a majestic Wild West by the sea. In this cathedral-like zone is the Grotta Perciata ("pierced" by clefts in the rock), followed by the Grotta del Presepe, or Creche Cave, where the limestone formations resemble a nativity scene, and the Grotta della Bombarda (the waves make a "bombarding" sound) with its interesting undersea rock formations visible from the boat. The remainder of the island tour takes in Punta Libeccio, with its lighthouse, and the southern half of the western coast, dotted with idyllic swimming spots (including several minicaves only accessible to swimmers) and around the southern tip of Marettimo. Along this last stretch is usually a stop at Praia Nacchi, a pebbly but beautiful beach with crystalline turquoise water gently lapping the shore.