How to Visit Naples Underground (And What to Expect)

Forty meters below the chaos of Piazza San Gaetano, there’s a passage barely wider than your shoulders. The walls are carved from soft tufa stone — Greek quarrymen cut this rock 2,400 years ago — and the air is cool and damp even when Naples is baking under 35-degree heat above.

I was not prepared for how layered it all is. This is not one site — it is dozens, stacked and connected across centuries of digging. Greeks quarried the tufa to build Neapolis. Romans turned the quarries into an aqueduct system that fed the city for 500 years. During World War II, Neapolitans sheltered from Allied bombing raids in these same tunnels, and you can still see their graffiti on the walls. Furniture, too. And somewhere beneath a nondescript apartment building on Via Anticaglia, there is a buried Roman theater where Emperor Nero reportedly performed.

That is what makes Naples Underground worth your time — the sheer improbability of it. An entire city exists beneath the one you are walking through, and most travelers never see it. Here is everything you need to know about getting down there.

In a Hurry?

What Naples Underground Actually Is

People say “Naples Underground” like it is one attraction. It is not. There are at least five major underground sites open to visitors, each from a different era and serving a completely different purpose. Here is the breakdown:

Napoli Sotterranea (Piazza San Gaetano) — the original, the famous one. This is the network of Greek-era quarries that became Roman aqueducts, then WWII bomb shelters. The tour takes you through ancient cisterns, narrow passages carved from tufa, and wartime refuges still marked with graffiti and drawings from people hiding during the bombings. You will also see the remains of a Roman theater buried beneath a modern apartment. The entrance is on Piazza San Gaetano, right in the historic center.

Napoli Sotterranea (Spanish Quarters) — a separate entrance and a different organization, confusingly with the same name. This one focuses more on the Greek aqueducts from around 400 BCE. The cisterns here are enormous, and WWII graffiti covers the walls. More intimate, slightly less touristy than the Piazza San Gaetano site.

Galleria Borbonica (Bourbon Tunnel) — built in the 1850s as an escape route for King Ferdinand II to flee from the royal palace to the military barracks. He never needed it. During WWII it became a bomb shelter, and afterward the city used it as an impound lot. There are still vintage Fiat 500s and Vespas down there from the 1950s and 60s, slowly decaying in the dark. It is the most visually striking of all the underground sites.

Catacombs of San Gennaro — early Christian burial chambers dating to the 2nd century CE. These hold the remains of Naples’ patron saint (San Gennaro) and feature some of the oldest Christian frescoes and mosaics in southern Italy. Located in the Sanita district, slightly outside the historic center.

Catacombs of San Gaudioso — smaller and darker than San Gennaro, with a more unsettling atmosphere. Named after a North African bishop who was buried here in the 5th century. The bone drainage practices here are… memorable. Not for the squeamish.

How to Get Tickets

Every underground site in Naples requires a guided tour — you cannot just buy a ticket and wander in on your own. The passages are complex, there is no signage underground, and honestly you would get lost within ten minutes.

For Napoli Sotterranea (Piazza San Gaetano): You can book directly through the official site, but I would recommend booking through a tour platform. The official site is only in Italian and the booking system can be clunky. Walk-ups are possible, but during peak season (April to October) the popular time slots fill up, especially the English-language tours.

For the Bourbon Tunnel: Same deal — book online in advance. They offer four different tour routes: the standard path, an adventure route with rafting on the underground water, a speleo-light route for those wanting to climb and squeeze through tight spaces, and a “darkness” tour done entirely by candlelight. The standard route is fine for most visitors.

For the Catacombs: Book through the Catacombs of Naples cooperative. They run both San Gennaro and San Gaudioso, and you can get a combined ticket for both.

Pricing is reasonable across the board. Most tours run between $12 and $22 per person. This is one of Naples’ best value attractions.

The Best Tours to Book

I have looked through what is available and picked four that cover the main underground experiences. Each one takes you to a different site, so they are not interchangeable — you could do all four over a couple of days if you are serious about going deep (pun intended).

1. Naples Underground Entry Ticket and Guided Tour

• Price: $21 per person
• Duration: 1.5 – 2 hours
• Provider: GetYourGuide

This is the flagship Napoli Sotterranea tour, and it is the one you should book if you only do one underground experience. Your guide takes you down 40 meters through Greek-era quarries, Roman aqueduct cisterns, and WWII bomb shelters. The narrow passage section is the part everyone talks about — a squeeze through a gap barely 50 centimeters wide, lit only by a candle. It is not actually dangerous, but if you are claustrophobic, it will test you.

The guides are passionate and know the history cold. Two hours flies by. The WWII shelter section, where you can still see drawings and personal items left behind by families who lived underground for months, is the most emotionally powerful part.

Best for: First-time visitors. This is the definitive Naples Underground experience.

Check prices and availability

2. The Bourbon Tunnel Guided Tour with Entrance Ticket

• Price: $12 per person
• Duration: About 1 hour
• Provider: GetYourGuide

At twelve dollars, this might be the best value underground tour in Naples. The Bourbon Tunnel is completely different from Napoli Sotterranea — where that one is ancient, this one is 19th century. King Ferdinand II ordered this tunnel built in 1853 as a secret escape route from the Royal Palace to the barracks near the port. He was paranoid about revolution (justifiably, as it turned out).

The tunnel was never finished for its original purpose. During WWII it became a shelter, and later the city used it as a judicial warehouse. That is why there are rusting 1950s cars and motorcycles piled up down there — seized vehicles that nobody ever came back for. Walking through this space feels like a post-apocalyptic movie set.

Best for: Visitors wanting something different from the standard ancient ruins experience. Also great for photography.

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3. Catacombs of San Gennaro Entry Ticket and Guided Tour

• Price: $15 per person
• Duration: 45 minutes
• Provider: GetYourGuide

The catacombs are the most historically significant underground site in Naples, but they feel different from the aqueduct tours. These are burial chambers — large, vaulted spaces carved into the hillside in the Sanita district, used from the 2nd century through the early medieval period.

What makes San Gennaro special are the frescoes. Some of the earliest depictions of Christian saints in Italy are down here, painted directly onto the rock. The scale surprises people too — these are not narrow tunnels. Some chambers are the size of small churches, with arched ceilings and carved alcoves for burial niches.

The tour is shorter than the Napoli Sotterranea one (about 45 minutes), but it is dense with information. The guides are volunteers from the local cooperative that manages the site, and their personal connection to the neighborhood adds something commercial tour operators cannot replicate.

Best for: History lovers, anyone interested in early Christianity, and visitors who want to see the Sanita district.

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4. Naples Underground Spanish Quarters with Guide

• Price: $18.14 per person
• Duration: 1 hour
• Provider: Viator

This is the “other” Napoli Sotterranea — accessed through the Spanish Quarters rather than Piazza San Gaetano. The experience is similar in theme (Greek aqueducts, Roman cisterns, WWII shelters) but the specific tunnels and chambers are different, and the groups tend to be smaller.

The Greek-era cisterns on this route are some of the most impressive — tall, cavernous spaces that make you realize just how much engineering went into Naples’ ancient water supply. The WWII shelters here still have graffiti and drawings on the walls, and the guides do a good job connecting the ancient and modern history.

If you have already done the main Napoli Sotterranea tour and want more, or if you are staying in the Spanish Quarters and want something close by, this is worth the time.

Best for: Visitors who want a less crowded alternative to the main Napoli Sotterranea, or those doing multiple underground experiences.

Check prices and availability

When to Visit

The underground stays around 15-16 degrees Celsius (about 60 Fahrenheit) year-round, regardless of what is happening above. That makes it one of the few attractions in Naples that works equally well in any season. In fact, it is a genuine relief on a scorching August afternoon.

Peak season (April-October): Book English-language tours at least 2-3 days in advance, especially for Napoli Sotterranea. The main Piazza San Gaetano tours run roughly every hour, but the English ones are less frequent. The Bourbon Tunnel is slightly easier to book last-minute.

Off-season (November-March): Walk-ups are usually fine. Smaller groups, more intimate experience, and the guides have more time for questions. The downside is that some sites reduce their tour schedule.

Time of day: Morning tours (10-11 AM) tend to draw fewer people than the afternoon slots. If you are doing Napoli Sotterranea, the first English tour of the day is your best bet for a smaller group.

How long to budget: Each individual site takes 45 minutes to 2 hours. If you want to do two underground sites in one day (which I would recommend — the Napoli Sotterranea plus either the Bourbon Tunnel or the catacombs), budget a full morning or afternoon.

What You Need to Know Before You Go

Claustrophobia is real down here. I don’t say this to scare you off, but be honest with yourself. The main Napoli Sotterranea tour includes a section where you squeeze through a passage about 50 centimeters wide while holding a candle. It lasts maybe 30 seconds. If that sounds awful, the Bourbon Tunnel and the catacombs are much more spacious. Or you can ask your guide about skipping the narrow section — there is usually an alternative route.

Wear layers. It is 16 degrees underground even when it is 35 above. That temperature shift hits hard. A light jacket or hoodie stuffed in your bag is enough. You won’t need it topside, but you will be grateful down there.

Comfortable shoes, not sandals. The floors are uneven stone, sometimes wet. Some sections involve steep stairs carved into rock. Closed-toe shoes with decent grip. I have seen people in flip-flops and it looked miserable.

Bring a phone with a flashlight. The tours are lit, but some sections are deliberately dim for atmosphere. Your phone light helps on the uneven stairs.

Photography is allowed at most sites, but flash photography is prohibited in the catacombs to protect the frescoes. The Bourbon Tunnel is actually great for photography — the abandoned cars in dim light make for dramatic shots.

Kids are welcome on most tours, but use your judgment. Children under 6 might find the narrow passages and dark spaces frightening. The Bourbon Tunnel’s standard route is the most kid-friendly. The catacombs — with their burial niches and bones — depend on the child.

Accessibility is limited. Most underground sites involve steep stairs and narrow passages. The Catacombs of San Gennaro are the most accessible, with ramp access and wider corridors. But none of the sites are fully wheelchair accessible.

What You Will See Underground

Naples sits on a layer of volcanic tufa — soft, porous rock deposited by eruptions from the Campi Flegrei volcanic system over hundreds of thousands of years. This rock is easy to cut but hardens with exposure to air, making it an ideal building material. Every major civilization that controlled Naples dug into it.

The Greek Layer (4th-3rd century BCE): The first major excavation. Greeks quarried tufa blocks to build the walls and temples of Neapolis. The quarries left behind enormous caverns that would later be repurposed.

The Roman Layer (3rd century BCE – 5th century CE): The Romans connected the Greek quarries into an elaborate aqueduct system that channeled water from the slopes of Mount Vesuvius into the city. These cisterns served Naples for over 2,300 years — the system was not decommissioned until the cholera epidemic of 1884, when open-air cisterns were blamed for spreading disease.

The War Layer (1940s): During WWII, the Neapolitan government converted the abandoned aqueducts and tunnels into air raid shelters. Tens of thousands of people sheltered here during Allied bombing campaigns. You can still see beds, furniture, and personal effects. Drawings on the walls — some by children — show airplanes, explosions, and soldiers. It is one of the most affecting things I have seen in any underground site anywhere.

The Bourbon Layer (1850s): The Galleria Borbonica was an entirely separate project — a military tunnel rather than a water system. Its later use as a city impound lot created the bizarre tableau of mid-century Italian cars and motorbikes decaying in a royal tunnel.

The Catacombs (2nd-5th century CE): The earliest Christian community in Naples buried their dead in chambers carved into the hillside north of the city center. San Gennaro, Naples’ patron saint, was interred here in the 5th century, and his tomb became a pilgrimage site. The frescoes on the walls and ceilings date from the 2nd through 10th centuries and represent some of the most important early Christian art in Italy.

Getting There and Getting Around

The major underground sites are scattered across Naples, so you will need to plan a bit.

Napoli Sotterranea (Piazza San Gaetano): In the heart of the Centro Storico, on Via dei Tribunali. The nearest metro station is Dante (Line 1), about a 7-minute walk. Look for the entrance on Piazza San Gaetano, next to the church of San Paolo Maggiore.

Napoli Sotterranea (Spanish Quarters): Entrance on Vico Sant’Anna di Palazzo. Walking distance from Via Toledo metro station (Line 1). The Spanish Quarters themselves are worth wandering before or after the tour.

Galleria Borbonica: Entrance at Via Domenico Morelli 40, in the Chiaia district near the waterfront. Closest metro: Piazza Amedeo (Line 2) or Municipio (Line 1). It is about a 10-minute walk from the seafront promenade.

Catacombs of San Gennaro: Located next to the Basilica of the Madre del Buon Consiglio, in the Sanita district. A bit further from the center — a 20-minute walk from the Archaeological Museum, or take bus C51 from Piazza Cavour. The Sanita neighborhood is rough around the edges but full of character, and the cooperative managing the catacombs has done a lot to revitalize it.

Can you combine underground tours with other Naples attractions? Absolutely. The Napoli Sotterranea at Piazza San Gaetano is a 5-minute walk from the Cappella Sansevero and the Veiled Christ — do both in one morning. The Bourbon Tunnel is close to the waterfront and Castel dell’Ovo. And if you are heading to Pompeii, the underground tours make for a great contrast — the buried city above versus the buried city below.

If you are spending time in the region, the Colosseum in Rome has its own underground level worth seeing, and a day trip to Capri makes a nice contrast to all the time spent below street level.

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