The principal island in the Pontine archipelago is one of the most naturally gorgeous and downright fun islands of Italy, and just far enough from the mainland to be an impractical destination for mass tourism. So much the better for those who do go to the trouble of making a trip here, because what you'll find is a rare Mediterranean gem that has kept its Italian identity intact and undiluted. It's not that Ponza is "undiscovered." On the contrary, it's a summertime escape that enjoys feverish devotion among the bella gente (the "nice" -- that is, financially sound and good-looking -- people) of Rome and Naples, who descend by the hordes here in July and August. This state of affairs is nothing new: Ancient Roman emperors favored Ponza as a summer retreat from their stifling urbs, and there are wonderful remains of that era in the so-called Grotte di Pilato, sea caves that were used as an eel farm, very near the port.

Long and skinny with scalloped bays that reduce its average width to about 1km (3/4 mile), Ponza is shaped like a sickle that's been chipped away by time and the elements. Though it was deforested centuries ago to reveal mostly arid, lizardlike contours, nature is quite striking on Ponza. The island's intricate 22km (14-mile) coastline is big on coves and promontories with weird and often spectacular rock formations that provide an endless supply of dramatic swimming breaks. The grandest of them all is the stunning bay of Chiaia di Luna, backed by an enormous sheer wall of lunar-yellow volcanic tufa.

Going to Ponza is all about living and breathing il mare (the sea). You either own or rent a boat (small, easy-to-pilot motorboats abound), and you spend your days puttering up and down the coast, swimming in coves and grottoes that aren't accessible by land, picnicking under the unrelenting Mediterranean sun, and developing a killer tan that you can be proud of when night falls and it's time to strut your stuff for fellow vacationers. By sunset, everyone goes for the evening passeggiata on the same street and for aperitivo drinks at the same bars.

Ponza has one main town, Porto, which is picturesque in a lived-in way; among the faded pastel houses stacked up behind the ferry landing are stylish independent boutiques, cheek by jowl with gritty marine hardware stores. This is a refreshing difference from more overtly charming Italian seaside towns, like Capri or Positano, that exist for tourism only. Ponza has a brief holiday season (July and Aug), but the rest of the year, it is a working island. There are no resorts on Ponza, no world-class hotels; the majority of accommodations are vacation rentals where function wins over form.

The repeat, moneyed visitors on Ponza, combined with the fact that there are very few foreign tourists to interfere with the entrenched rhythms and habits of the place, can make for a bit of a clubby atmosphere, especially in peak season. However, this microcosm of Italian privilege can also be great fun to watch. Of course, if you want to avoid that scene altogether, just come in the gorgeous shoulder months of May, June, and September. Locals will tell you this is when their island really shines. Days are warm but mornings and evenings are crisp, and the colors of the flora and sea are all the more vivid outside of high summer.

Two other islands in the Pontine archipelago not served by regular ferry, Palmarola and Zannone are classic day trips from Ponza, each just 30 minutes away by boat. To the west, Palmarola is an unexpected slice of Robinson Crusoe in the Mediterranean; its turquoise seas and splendid coves, evocative of pirates and castaways, seem like they've been transplanted from the South Pacific or the Caribbean. To the northeast, Zannone is a nature reserve with quiet hikes, dense forests, and wild sheep running free.