As Rome expanded, it needed a bigger port so Ostia was abandoned. When the Roman Empire fell, Ostia became a ghost town - even the river moved away over time and Ostia became buried under river mud. This is what preserved it and leads some to now compare its preservation to that of Pompeii.
Rachael, the guide, brought this tour to life for us. We really got a feeling for what life was like in a city like Ostia back then. Only 15 people were on the tour. Also, it was good to escape the hustle and bustle of Rome for awhile.
Ostia was the highlight of our trip for my daugher and Massimo (our guide from Dark Rome tours) made it special. He was extremely knowledgeable and made Ostia accessible for us in way it would not have been had we visited on our own because there is such limited signage. Our knowledge of ancient Rome was much enhanced by this tour.
Our guide Massimo was entertaining as well as well-informed. We learned a lot on this tour. Ostia is very large and quite well preserved, a real insight into Ancient Rome and its economy.
The best way to reach Ostia is on a tour (click the tour & tickets tab) or on a local train. Catch the metro to Piramide, which is also the Roma Porta San Paolo train station. Follow the signs to Lido, take the train (they only go in the one direction) and get off at Ostia-Antica. Then cross the sky-bridge and continue straight until you reach the parking lot: the entrance to Ostia Antica is on your left.