The volcanic caldera west of Naples contains some of Italy's most underrated archaeological sites alongside active fumaroles and hot springs. Visit the Roman Flavian Amphitheater at Pozzuoli (third largest in the Roman world), the Solfatara volcanic crater, and the submerged ruins at Baia.
The Phlegrean Fields (Campi Flegrei) is a vast active volcanic caldera just 15 km west of Naples in Campania, Italy, packed with underrated Greek and Roman ruins alongside steaming fumaroles and hot springs. It is reached in 30-40 minutes by the Naples Metro Line 2 or the Cumana train to Pozzuoli (around €5), making it one of the easiest archaeological day trips from the city. A practical one-day arc bases itself in Pozzuoli: start with the Flavian Amphitheatre, the third largest in the Roman world, whose remarkably intact underground chambers (hypogeum) once raised animals and scenery into the arena. From there the Solfatara crater traditionally offered a walk across a shallow volcanic basin of bubbling mud and sulphurous fumaroles, though access can be restricted for safety, so its status should be checked before setting out. The Rione Terra, Pozzuoli's ancient acropolis, and the Serapeum (a Roman market that records the area's slow rise and fall of ground level, known as bradyseism) sit near the port. A short hop west reaches Baia, where the submerged Roman villas of the underwater archaeological park can be seen by glass-bottom boat or snorkelling tour, plus the Aragonese castle museum and the Baths of Baia terraces. Lake Avernus, the mythical entrance to the underworld, and Cuma, with the Cave of the Sibyl, complete the area for those with extra time. Public transport links the sites, but a hired car or a guided tour eases the hops between Pozzuoli, Baia and Cuma. For food, Pozzuoli's harbour is known for some of the freshest fish near Naples, with a lively morning market and seafront trattorias. Spring and autumn are most comfortable for the exposed sites, and mornings are best for the fish market and clearer light. Sturdy shoes are useful for the uneven volcanic and archaeological terrain.
Highlights
- Pozzuoli Amphitheater
- Solfatara volcanic crater and fumaroles
- Submerged Roman Baia ruins (snorkeling)
- Fresh fish market at Pozzuoli port
Tips for visiting
- Take Metro Line 2 or the Cumana train from Naples to Pozzuoli, around 30-40 minutes, as the base for the area.
- Check current access to the Solfatara crater before going, as it can be closed for safety.
- See the Baia underwater Roman ruins by glass-bottom boat or a snorkelling tour booked in advance.
- Use a car or a guided tour to link Pozzuoli, Baia and Cuma, which are spread out and awkward by bus.
- Time lunch around Pozzuoli's harbour for some of the freshest fish near Naples.
- Wear sturdy shoes for the uneven volcanic ground and archaeological sites.
When to visit
Spring and autumn bring comfortable temperatures for the exposed sites; arrive in the morning for clearer light and Pozzuoli's lively harbour fish market.
Accessibility
The sites are spread across uneven volcanic and archaeological terrain with steps and unpaved paths, making the area challenging for wheelchair users; the Flavian Amphitheatre and parts of Pozzuoli are more manageable than the crater and coastal ruins. The Baia underwater tours require boarding boats.
Frequently asked questions
What is there to see in the Phlegrean Fields?
Highlights include Pozzuoli's Flavian Amphitheatre, the Solfatara volcanic crater, the submerged Roman ruins at Baia, the Serapeum and the Cave of the Sibyl at Cuma.
How do visitors get there from Naples?
Take Metro Line 2 or the Cumana train to Pozzuoli, about 30-40 minutes and roughly €5. The sites are spread out, so a car or guided tour helps link them.
Can the underwater ruins at Baia be visited?
Yes. The submerged Roman villas of the Baia underwater park can be seen on glass-bottom boat trips or guided snorkelling and diving tours.
Is the Solfatara crater open?
Access to the Solfatara has at times been restricted for safety reasons, so visitors should check its current status before planning a walk across the crater.