This low, flat island between two arms of the river is rich in history. It was the site of Portus, the harbour that the emperors Claudius and Trajan built to supply Rome, and the ruins of warehouses, docks and a hexagonal basin can still be seen. Ostia Antica, the old port town, is only a short ride away.
For a ride that began in the Castelli Romani, the hills south-east of Rome, this is a westward finish, down to the coast. The roads are flat, straight and often busy, with traffic lights and roundabouts, and the surface is mixed, with patches and potholes. The Via del Mare and the Via Ostiense connect Rome to the coast, and they are heavily used by Romans going to the beach, especially at weekends, so weekdays and early mornings are best. Pine woods and reed beds line parts of the coast, and the air smells of salt and resin.
The coast has a strange history. Ostia Antica was a major port for centuries and is now one of the best-preserved Roman towns, with a theatre, shops and mosaics that are far less crowded than Pompeii. Lido di Ostia, the modern seaside town, was developed in the 1920s and is where many Romans spend summer weekends. In winter, the beach is quiet, and the seafront restaurants serve fresh fish and fried calamari.
Fuel is plentiful in Fiumicino and Ostia, with large stations on the main roads. The area has many fish restaurants, especially around the old fishing port of Fiumicino, where the catch is landed each morning, and a plate of spaghetti with clams is the typical meal. Bars along the beach serve coffee and pastries.
Walk out to the sea wall if you have time. The mouth of the Tiber is muddy and plain, but there is something satisfying about seeing where the river that gave Rome its life reaches the sea.