A smell of sulphur sometimes drifts over the coves of Ischia, a quiet reminder that this island in the Bay of Naples was born of volcanoes. Hot water seeps up everywhere here: in the thermal gardens, in the coves, even into the sea itself. Ships anchor off the northeast coast, and tenders bring passengers ashore at Ischia Porto, an almost perfectly round harbour that was once a crater lake before being opened to the sea in the 19th century.

From the Porto to the Ponte, the Classic Walk

The landing opens straight onto the lively quays of the Porto, with their cafés and shops. From there, an elegant avenue, Corso Vittoria Colonna, runs east past ceramic shop windows, gelaterias, and baroque churches. Half an hour of strolling leads to the town's oldest quarter, Ischia Ponte, a former fishing village of narrow lanes and weathered façades. The walk is flat and pleasant, and buses cover the same route for those who'd rather save their legs. Along the way, bakeries offer sfogliatelle still warm from the oven, and grocery stores line up giant lemons, sun-dried tomatoes, and bottles of oil: the Bay of Naples announces itself first through its scents.

The Castello Aragonese, Sentinel on Its Islet

At the far end of the Ponte rises the island's most striking sight: a spire of volcanic rock planted in the sea, crowned with walls and linked to land by a 220-metre jetty. The current fortifications of the Castello Aragonese date to 1441, under Alfonso of Aragon, but the rock has carried defences since antiquity. An elevator cut into the stone, or the old mule path for the more energetic, leads up to the upper terraces: churches, crypts, hanging gardens, and panoramic views over the whole gulf follow one after another along the visitor route. From atop the ramparts, the view stretches all the way to Vesuvius on a clear day, and the rooftops of the old town spread out below like a scale model. This is the highlight of the stop, the one not to skip.

Thermal Baths, Beaches, and Villages on the Other Side

Ischia would be poorly summed up by its castle alone, however photogenic it may be. Its sandy beaches, rare in this region, line the town centre: the Lido unrolls its beach huts just minutes from the Corso, between rocks and pine groves, with the castle in full view for anyone swimming out toward the open water. Spa-goers come from all over the world for the waters: thermal gardens with dozens of pools, or, simpler and free, Sorgeto Bay on the other side of the island, where scalding springs bubble up among the pebbles straight into the sea. You settle in as if into a bath, choosing your temperature by how close you sit to the source; regulars stay for hours.

Island buses extend the range further: Forio with its open-air markets, or Sant'Angelo, a pedestrian hamlet in the south with colourful boats, rank among the loveliest destinations for the day. Keep an eye on the clock, though: the island road winds a great deal, public vehicles fill up fast in summer, and the island proves larger than it looks from the ship's deck.

Reference Points for the Day

• From the landing to the old quarter: 30 minutes on foot along the Corso, or local bus.
• Castello Aragonese: admission ticket includes the elevator; allow 1.5 to 2 hours.
• Lido beach: within walking distance of the landing.
• Forio or Sant'Angelo: by bus or taxi, a half-day round trip.

In the evening, as the castle lights up above the dark water and the terraces along the Ponte serve the first plates of spaghetti alle vongole, it's easy to understand why the Romans themselves came here to soothe both body and mood. Ischia may not cure everything, but it leaves you reconciled with the Mediterranean for a long time to come.