Baia: Sunken Roman City and Castello Aragonese

Baia offers two distinct archaeological perspectives: beneath the surface of the sea lie the remains of an ancient Roman coastal city, while the Castello Aragonese di Baia stands on Roman residential structures. Bradyseism caused the city to sink below sea level; mosaics, statues, columns and architectural structures have been preserved a few metres beneath the water’s surface. The Parco sommerso di Baia is a protected marine area in the Gulf of Pozzuoli.

The Sunken Sites of Baia

In the Parco Archeologico Sommerso di Baia, Roman villas, thermal baths, roads and harbours have been preserved across 180 hectares at depths of four to eight metres. The sites form an extensive underwater archaeological landscape. Since 2001, the sites have been made accessible through guided scuba dives, snorkelling tours, glass-bottom boat trips and a small tourist submarine. Before making plans, check which of these activities are currently available.

The underwater sites and the Castello offer different ways to explore Baia and its history: here, the remains of a coastal city beneath the surface; there, a fortress with Roman traces and a museum. If you are looking for a holiday apartment in Baia, this distinction can help you decide what to focus on during your stay.

Castello Aragonese, the Museum and Roman Traces

The Castello Aragonese di Baia was built towards the end of the 15th century as part of the fortification programme promoted by the Aragonese dynasty in the Kingdom of Naples. The complex stands on the remains of Roman residential structures. Today, it houses the Museo Archeologico dei Campi Flegrei, which collects and displays archaeological finds from Baia, Cuma, Puteoli and Liternum.

Notable exhibits include plaster casts from Baia, considered a unique testimony to Hellenistic and Roman casting techniques. The “Mercurio” area also connects architecture with dating: according to current knowledge, it contains the oldest example of a large-scale hemispherical concrete dome. The “Mercurio” hall is dated to the time of Augustus.

A visit to the Castello takes you through various parts of the complex, some far apart, as far as Piazza d’Armi. From there, you can enjoy panoramic views across the entire Gulf of Naples. The route combines views of the fortress and its Roman remains with a sweeping outlook over the gulf.

Getting There and Choosing the Focus of Your Stay

From Napoli Montesanto, you can take the EAV Ferrovia Cumana to Fusaro or Lucrino. From there, take an EAV bus or walk about one kilometre. Interurban EAV buses from Fuorigrotta or from Piazza Garibaldi or Porta Nolana also run to the Baia – Via Castello stop, a short walk from the entrance to the Castello Aragonese di Baia. Check the latest EAV information before travelling, as getting-there details may change.

When planning your day, it is worth treating the routes to the underwater sites and the tour of the Castello as separate activities. The stops described for a visit to the castle take you as far as Piazza d’Armi; various access options are listed for the underwater archaeological sites, but you should check in advance which are currently available.

Discover More Destinations

Discover more destinations: Schiazzano, Pimonte, Capri, Afragola, Casola di Napoli, Caivano, Torre Annunziata, Roccarainola.

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