The coastal area along which the Etruscans had for centuries carried purple dye from Phoenicia, iron from the island of Elba, and vases from Corinth enhancing Tarchna's beauty, has today become Riviera degli Etruschi (Riviera of the Etruscans) of which the Lido of Tarquinia is also a part. It stretches out for 85km, from the Chiarone locality bordering with Tuscany in the north, to Ladispoli near Rome in the south.
From Tuscany to just before Civitavecchia the coast is covered with sand dunes; then from Civitavecchia southwards it becomes narrow and rocky. The following places, from north to south, are the most important directly concerning Tarquinia:

Riva dei Tarquini, a vast pinewood housing holiday villages;

Torre del Castellaccio, erected in the 14th century and surrounded by a defensive wall of which only little remains, served as a lookout post for landings along the Arrone;

Torrente Arrone, with a beautiful estuary;

Marina Velca, a residential centre with golf courses, a swimming pool and other facilities;

The Marta River, where the ancient Etruscan port of Martanum was located;

The Lido of Tarquinia;

Port Clementino and Gravisca;

The Saline (Saltworks);

The Mignone River;

Sant'Agostino, a small inlet sheltered by a rocky headland, with a pinewood behind it. The Bertalda Tower, now no longer existing, once guarded its harbour.

The seaside resort of Tarquinia Lido, located between the mouth of the Marta and the remains of Port Clementino, is about 5 kilometres from the town. It has long stretches of sandy beaches and is equipped with numerous, well-functioning, tourist infrastructures. Since the 1960s it has undergone rapid redevelopment with the construction of bathing establishments and modern summer residences.
Port Clementino, the ruins of which emerge near a former sea colony, was once a focal point for the trading of grain cultivated in the area, bound for Rome and other Mediterranean ports. Over the centuries, continual heavy swells and the weathering of winds made all attempts to restore the pier useless. As a result, the port of Tarquinia fell into decline, having to give way to the port of Civitavecchia, which took its place in providing an access to Rome.
The Saline, to the south, were built in the early 1800s. They supplied the city of Rome with salt for centuries. At one stage they were even a penal colony. At present, the Saline spread out over an area of 90 hectares, 10 of which were used as salt basins (where seawater was collected) and 80 as evaporating basins (where salt was obtained). The plant would still be operative if the area making up the Saline had not been proclaimed a Nature Reserve for the Populating of Animals.
The coastal area between Tarquinia and Civitavecchia is called Sant'Agostino, where a very charming little hamlet is sited. According to legend, while St. Augustine was meditating on the mystery of the Trinity on the small inlet beach bearing his name, he saw an angel in the guise of a child who said it wanted to cross all the water in the sea in a hole in the sand. The saint understood its allegorical meaning, realising that it was impossible to grasp transcendental truths.