Terme di Nettuno (Baths of Neptune)
The floor stops you before anything else. Two rooms lead you toward the cold bath, and in each one the mosaics have survived nearly two millennia underfoot: first Amphitrite riding a sea-horse flanked by tritons, then Neptune himself driving a four-horse chariot through a sea of dolphins. These aren't ceiling frescoes preserved by accident — they were walked on, daily, by people stripping off for a bath.
The Baths of Neptune sit just off Ostia Antica's main street, the Decumanus Maximus, behind an arcaded portico that once announced this as a serious civic building. The palaestra to the west still has the footprint of its marble colonnade. The latrine near the entrance has its own small masterpiece: a Nilotic scene of pygmies, crocodiles and amphorae-laden boats.
💛 What travellers fall for
People who've been twice tend to mention the elevated terrace above the portico — a staircase takes you up so you can look down across the mosaic floors from above, which is the only way to read the full composition of the Neptune panel. Worth finding before the school groups arrive.
The story behind Terme di Nettuno (Baths of Neptune)
The baths began in the late 1st century AD but the structure you walk through today is largely Hadrian's. He rebuilt the complex between AD 117 and 138, at a documented cost of two million sesterzi. His successor Antoninus Pius completed the work in AD 139, the first year of his reign.
Fire damage under Marcus Aurelius brought a restoration by a local notable, Publius Lucillius Gamala. Further changes followed in the 3rd and 4th centuries — the original calidarium was abandoned, and the laconicum was converted to take its place. By the 6th and 7th centuries, the building had come full circle: its rooms were used for burials.
Good to know
Reach Ostia Antica via Metro Line B to Piramide, then the Lido train from Roma Porta San Paolo — about 30 minutes, covered by a standard metro ticket. The site opens at 8:30; Tuesday through Thursday right at opening gives you the mosaics in quiet. Admission is €18 and single-entry only.
May through October is the comfortable window, with temperatures between 21°C and 28°C. In June, July and August the site bakes by midday — arriving at the 8:30 opening buys you two cooler hours before the heat peaks; November and December bring short days and real rain.
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What travellers say about Terme di Nettuno (Baths of Neptune)
The mosaics in the Baths of Neptune are not to be missed when exploring the archeological site of Ostia Antica. It would have been easily missed if not for the map I purchased for a few euros at the ticket office. It also helps to listen to the Rick Steves' audio guide prior to your visit. There are steps leading up to a viewing area overlooking the very well-preserved mosaics. An absolutely amazing view with the sound of birds chirping. Loved it!! We had a very enjoyable visit on a beautiful morning in the month of May.
Some parts of Ostia Antica are poorly displayed for the public, however it is a wonderful site and still an active excavation site in some places.
Ostia Antiqua is the most amazing place in Rome. A lot of walking, but totally worth it. The collection in the museum is cool, but the site itself is mind numbing! Hit up YouTube for the Rick Steve's guide before going, the set your expectations higher, because they are still finding new stuff
The first high view you get of Ostio Antica. Beautiful ruins with a 360 view. Hard to take photos however, given the caution tape used to keep people out of the areas with delicate mosaics.
Loved it everything was awesome even the toilets
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