Getting to Formia by train is particularly handy.
There are trains (www.trenitalia.com) every hour from Rome and Naples, the journey takes about 1 hours, then it is a 10-minute walk or taxi ride to reach the boarding point.
The island of Ventotene belongs to the province of Latina and lies off the coast of Lazio and Campania. The main boarding port to reach the island is Formia, from where hydrofoils and ferries of Laziomar leave. Laziomar provides the public transport service to Ventotene with at least 2 daily connections.