Ancient Roman Port of Puteoli Revealed Beneath the Bay of Naples
Archaeologists are uncovering the remarkable underwater remains of Puteoli, the Roman Empire’s principal commercial port before the construction of Portus and the expansion of Ostia. Hidden beneath just three to five metres of water near modern-day Pozzuoli, the submerged city is providing an extraordinary glimpse into the infrastructure that once powered Rome’s Mediterranean trade network.
The ongoing underwater investigations have revealed warehouses, workshops, porticoes, harbour installations and other commercial buildings preserved beneath the Bay of Naples after centuries of volcanic ground movement. Together, these discoveries are reshaping understanding of one of the empire’s most important economic centres.Image Credit : The American Institute for Roman Culture
Rome's First Great Commercial Gateway
Long before Portus became Rome’s main maritime hub, Puteoli served as the capital’s primary gateway for goods arriving from across the Mediterranean.
Its strategic location on the Bay of Naples connected Rome with trading partners in Egypt, North Africa, the Levant and the wider Mediterranean world, making it one of the busiest ports of the Imperial period.
Over the centuries, however, much of the ancient harbour gradually disappeared beneath the sea due to bradyseism—a geological process unique to the volcanic Campi Flegrei region that causes the land to slowly rise and sink.
Today, almost two kilometres of the ancient harbour district lie underwater.
Advanced Underwater Archaeology Reveals Hidden City
The discoveries form part of an ambitious archaeological programme running from 2021 to 2027 under the direction of underwater archaeologist Dr Michele Stefanile of the Istituto Italiano per l’Archeologia Marittima e delle Strutture Sommerse.
Supported by Ancient Rome Live through its Expandere Conscientiae Lumen (ECL) Grant, the project combines cutting-edge technologies including:
- Remotely Operated Vehicles (ROVs)
- Underwater photogrammetry
- 3D digital modelling
- Geographic Information Systems (GIS)
- High-resolution underwater mapping
These techniques allow researchers to digitally reconstruct the ancient port while documenting fragile archaeological remains without disturbing them.
Recent dives conducted by Ancient Rome Live Director Darius Arya and Dr Stefanile revealed exceptionally preserved Roman structures, including a marble-cutting workshop and walls that still retain original wooden elements despite spending nearly two millennia underwater.
Lost Nabataean Temple Rediscovered
Among the project's most remarkable achievements is the rediscovery of the submerged Temple of the Nabataeans, believed to be the only known Nabataean temple ever identified outside the ancient Nabataean Kingdom.
Although the temple was first located during the 1980s, funding shortages prevented further study and its precise location was eventually lost.
After almost twenty years of searching, Dr Stefanile's team relocated the structure during the project's first survey season in 2021.
Excavations revealed that the temple had remained exceptionally well preserved beneath thick layers of Roman concrete added during the 2nd century AD after Emperor Trajan annexed the Nabataean Kingdom.
The discovery offers rare evidence of the diverse communities that lived and traded within Rome's busiest commercial port.
Ancient Granaries Could Rewrite Roman Trade History
Researchers also believe the submerged granaries of the vicus Annianus may become one of the most significant discoveries of the entire project.
These enormous storage facilities once handled grain shipments arriving from Egypt before supplies entered Rome's food distribution system.
The archaeological evidence closely matches ancient written sources, including the famous Sulpicii wax tablets, which document financial transactions and loans linked directly to grain storage in Puteoli.
According to Dr Stefanile, the exceptional preservation of timber construction and internal architectural features provides a unique opportunity to study how Roman granaries operated.
He described the site as potentially the only place in the world where archaeologists can examine the internal organization of a Roman granary in such remarkable detail.
A Forgotten City of Imperial Rome
Despite its historical importance, Puteoli has often remained overshadowed by better-known Roman sites such as Pompeii, Ostia and Rome itself.
Darius Arya believes the city's significance has long been underestimated.
Before Portus became Rome's principal harbour, Puteoli served as the empire's commercial heart, linking merchants, bankers and ships arriving from every corner of the Mediterranean.
The city also stood alongside nearby Misenum, home to the imperial fleet, and Baiae, Rome's luxurious seaside resort, forming one of the wealthiest regions of the ancient empire.
Puteoli itself featured a stadium, an enormous basilica and an amphitheatre built even before the Colosseum, highlighting its importance within Imperial Rome.
Preserving an Underwater Heritage Site
Researchers hope the ongoing investigations will eventually transform the submerged archaeological landscape into an accessible underwater heritage destination.
Digital documentation, conservation work and continued excavation are expected to reveal additional buildings and harbour infrastructure over the coming years.
As exploration continues, Puteoli promises to become one of the world's most important underwater archaeological sites, offering an unparalleled window into the commercial engine that sustained the Roman Empire for centuries.
Conclusion
The submerged city of Puteoli is transforming our understanding of Rome's maritime economy. Preserved beneath the waters of the Bay of Naples by centuries of volcanic ground movement, its warehouses, temples, workshops and granaries reveal the immense scale of the empire's commercial network before Portus rose to prominence. Continued underwater exploration is expected to uncover even more evidence of the city that once served as Rome's greatest gateway to the Mediterranean.