The best way to get in Sicily is flying to Palermo or Trapani Airports from where you  can reach Trapani harbour and take the ferry boat to Marettimo

There are also two shipping Companies, “Grimaldi Lines” and “Tirrenia Lines”, from Genova, Livorno and Napoli

From Palermo you can reach Trapani in several ways: Taxi, Bus or private minivan. Connections from Trapani to Marettimo is with “Siremar” and “Ustica Lines” Shipping Companies. The travel takes approximately 1 hour and 15 min with the speed boat and 2 hours and a half with the ferry boat

For timetables visit following links