Formia Tourism: TripAdvisor has reviews of Formia Hotels, Attractions, and Restaurants making it your best Formia resource. Things to Do in Formia, Italy: See TripAdvisor's traveler reviews and We have reviews of the best places to see in Formia. Lungomare Santo Janni. Formia is a city and comune in the province of Latina, on the Mediterranean coast of Lazio (Italy). It is located halfway between Rome and Naples, and lies on the Roman-era Appian Way. It has a population () of 36, Contents. [hide]. 1 History; 2 Geography; 3 Main sights ; 4 Sport; 5 Transportation; 6 Twin Formia lies on the Tyrrhenian Sea, in southern Lazio, close to the town of.