Scavi Tour vs. Vatican Grottoes: What's the Difference?

“Underground St. Peter’s” is not one place — it is two distinct levels stacked beneath the Basilica floor, and they are booked in completely different ways. Confusing them is the most common planning mistake visitors make. This guide explains exactly what the Vatican Grottoes and the Scavi Necropolis are, what you see in each, and how to get into them — so you book the right experience instead of discovering the difference at the door. If you just want the papal tombs and the original 4th-century walls, the guided underground tour is the straightforward choice.

The Two Levels, Explained

Picture the Basilica as a building with two basements:

Level 1 — the Vatican Grottoes. Directly beneath the main Basilica floor. This is the upper crypt: it holds dozens of papal tombs, the Confessio above St. Peter’s Tomb, and surviving fragments of the original 4th-century Constantinian basilica. This is the level the guided underground tour visits.
Level 2 — the Scavi (the Necropolis). One level deeper still, at the original 1st-century ground level. This is an excavated Roman cemetery, and at its heart sits the burial site identified as the tomb of St. Peter himself.

Both are underground; only one of them is part of a normal guided tour.

Side-by-Side Comparison

	Vatican Grottoes	Scavi / Necropolis
Depth	Upper crypt, just below the Basilica floor	Lower level, 1st-century ground
What you see	Papal tombs, the Confessio, 4th-century Constantinian walls	Roman necropolis, the tomb identified as St. Peter’s
On the underground tour?	✓ Yes — included	✗ No — separate permit only
How to book	Booked as part of the guided tour	Email the Vatican’s Ufficio Scavi months ahead
Lead time	Book days or weeks ahead	Book 3–6 months ahead
Group size	Standard tour group	Small groups of around 12
Minimum age	No special age limit	Young children not permitted (around age 10 minimum)
Guide	Licensed Vatican tour guide	Vatican archaeologist / specialist

What the Vatican Grottoes Tour Covers

The Grottoes are what most people mean when they say they want to go “underneath” St. Peter’s. On the underground tour featured on this site, a licensed Vatican guide leads you below the main floor with radio headsets so the commentary carries clearly. Down there you see:

The papal tombs lining the underground walls — popes across many centuries, including several from recent memory.
The Confessio, the small sunken marble crypt directly beneath Bernini’s Baldachin, looking down toward St. Peter’s Tomb.
The original 4th-century Constantinian walls — and on this tour you can actually touch them, a tangible link to the basilica Emperor Constantine raised over the site some 1,700 years ago.

This is the level that delivers the “underground St. Peter’s” experience for the overwhelming majority of visitors — and it slots neatly into a half-day in Rome.

What the Scavi Necropolis Tour Covers

The Scavi tour is a different proposition entirely. It descends to the 1st-century Roman necropolis — a street of pagan and early-Christian mausoleums that was buried when Constantine built his basilica on top of it. The tour ends at the burial niche archaeologists identify as the tomb of St. Peter.

It is a serious, restricted experience:

It runs roughly 90 minutes and is led by a Vatican archaeologist, not a tourism guide.
It must be booked directly with the Vatican’s Ufficio Scavi (Excavations Office) by email, typically 3–6 months in advance. There is no online ticket page and no third-party reseller.
Capacity is tiny — on the order of 250 visitors per day in groups of about 12.
Young children are not admitted — the minimum age is around 10, and ID may be checked.
The ticket cost is modest — roughly €20 for adults and €14 reduced per the Fabbrica di San Pietro — but the real limiting factor is access, not price.

If your travel dates are fixed and close, the Scavi is realistically off the table; the lead time alone rules it out for most trips.

Which Should You Choose?

For nearly all visitors, the decision is straightforward:

Choose the Vatican Grottoes (the guided underground tour) if you want the papal tombs, the Confessio, the 4th-century walls, a licensed guide, and the flexibility to book on a normal travel timeline. It also pairs the underground portion with a full guided walk of the Basilica and an optional dome climb.
Choose the Scavi only if you are planning Rome months ahead, are travelling without young children, and specifically want to stand in the 1st-century necropolis at the deepest identified tomb site — and are prepared for an email-only booking process that may not come through.

The two are not really competitors; one is a flexible, guide-led highlight of a Rome trip, the other is a niche pilgrimage experience that demands long-range planning. Most travellers booking now should choose the Grottoes.

Ready to Book?

The St. Peter’s Basilica underground tour takes you into the Vatican Grottoes with a licensed Vatican guide and radio headsets — the papal tombs, the Confessio above St. Peter’s Tomb, and the original 4th-century walls — plus a full guided walk of the Basilica and an optional Michelangelo dome climb. It is rated 4.8/5 by 4,144 guests, costs from $38.59 per person, and carries free cancellation up to 24 hours before your start time. Check availability and book →