If you want to see both ancient and modern Rome, grab your swimsuit, towel, and sunblock, and take the Roma-Lido urban railway (operated by ATAC) from the Roma Porta San Paolo station (see Rome/Aventino-Testaccio). It is directly next to the line B (blue line) metro station Piramide, and within walking distance (500m) of the Roma Ostiense train station. All ATAC tickets and passes for Rome are valid on this urban railway. Departures are about every 15 minutes, or during Sunday and public holidays every 30 minutes; the whole trip takes about 40 minutes. The train lets you off at the Ostia Antica station across one of the highways that connects Rome with the coast. It's just a short walk to the Ostia Antica excavations. Later, board the train again to visit Lido di Ostia and the beach.

• 41.756812.30261 Ostia Antica railway station (Stazione di Ostia Antica). (updated Jul 2022)
• 41.733112.28382 Lido di Ostia Centro railway station (Stazione di Lido di Ostia Centro), P.le della Stazione del Lido. (updated Jul 2022)
• 41.72709112.2950653 Stella Polare railway station (Stazione di Stella Polare). (updated Jul 2022)
• 41.720312.30864 Castel Fusano railway station (Stazione di Castel Fusano). (updated Jul 2022)
• 41.714312.321825 Cristoforo Colombo railway station (Stazione di Cristoforo Colombo). (updated Jul 2022)

There is also a bus, number 070 departing from EUR Fermi (metro B) and going to the Castelporziano beach.

From the Fiumicino Airport there is a regional bus (COTRAL) departing from Terminal 2 heading to Ostia central station every 40 minutes; the trip takes about a half hour.

41.758312.29761 Ostia Antica (Parco Archeologico di Ostia Antica) (Arriving from Rome, get off at Ostia Antica station, a couple of miles from the beach area). From 08:30. Closing time varies according to the season. Closed Mondays. Admission €8 (€4 for EU residents between 18 and 25), maps €2.  

Originally a colony of Rome, Ostia grew to become the major port of the city. It was situated on the mouth of the Tiber, the word Ostia meaning "mouth". The town's growth started in the late Republic, but expanded rapidly under the Emperors Claudius and Trajan. The town was deserted after Rome's fall in 476 AD, and the buildings fell into ruins which were in turn covered by sand and mud from the Tiber, preserving them. The ancient town remained farmland until excavations took place in the late 19th and early 20th centuries, and now most of the old town is uncovered, giving the visitor an idea of what life was like in an Ancient Roman commercial town during the height of the Empire. The ruins are similar to those in Pompeii, but there are no wealthy houses in Ostia. The archaeological site is vast, with plenty to see to occupy a full day. You will need to wear good footwear.

In Ostia Antica, you should buy a guide book from the ticket office when you enter. Without a guide book, you will see lumps of stone everywhere. With a guide book, you will understand what buildings stood where those lumps of stone now lie. On your tour look out for:

• The Forum, with its Capitol. The Temple's podium is still in place, as are the walls of the cellar where the cult statues were kept. You get an appreciation of how huge Roman temples were.
• The Piazza of the Corporations, behind the theatre, preserves the offices of trade guilds or merchants from various parts of the world, each office identified by its mosaic floor.
• Ostia is famous for the ancient apartment buildings that are very well preserved. The town's population were poor dock workers living in large apartment buildings. These buildings can be explored to one storey in height, with narrow stairways and corridors leading to small rooms. There are also the remains of more wealthy houses, such as the House of Cupid and Pysche, with very rich marble decorations. You get a real feel for how these people lived 2,000 years ago.
• The small museum contains the main finds from the excavations, ranging from cult statues to small bits of sculpture.
• The ancient warehouses and docks. These are well preserved and look very much like those of the 19th century. The ancient kerbs and pavement are still in place as they are in Pompeii and Herculaneum.
• Visit the two Baths with their beautiful and famous mosaic floors.

• 41.7592712.301242 Ostia Castle. This is close to Ostia Antica, on the other side of the railway line and Via del Mare in the small village of Ostia Antica. It was built in 1483 by Giuliano della Rovere, who later became Pope Julius II. Much of the building material consisted of bricks pilfered from Ostia Antica.  
• 41.73472212.3197223 Pinewood of Castelfusano. Easily accessible from the stations of Cristoforo Colombo or Castelfusano, and the suburb of Infernetto.  
• 41.7791612.266664 Portus. Although Rome's original harbour was at Ostia Antica, but in the Imperial period two harbour basins were added to the north. Around AD 46 the Emperor Claudius constructed a new harbour with two long curving moles projecting into the sea. The harbour opened directly to the sea to the north-west protecting it from the prevailing south-west wind. It connected with the River Tiber by a channel on the south-east. The harbour was known as Portus (Latin for "harbour") and the Via Portuensis still connects Rome with the area. In 103 AD Trajan constructed another harbour farther inland, a hexagonal basin. The basin itself is now a reedy lagoon and remains of the many warehouses can still be seen. Like many points of archaeological interest in the area the port is unfortunately not open to the public without making an appointment. Details at ^{[dead link]}.  
• 41.73455812.3186565 Villa Sacchetti, Viale Mediterraneo, 52. Built in 1624-1628 for the Sacchetti family, close associates of Pope Urban VIII, and was the first architectural work of Pietro da Cortona.[1] The villa is now known as Villa Chigi since its acquisition by the Chigi family in the 18th century. (updated Jul 2022)