You can easily reach to Oplontis using the Circumvesuviana railway (tel. 800-053939 toll-free within Italy; www.vesuviana.it) running between Naples, Sorrento, and Poggiomarino/Sarno; get off at Torre Annunziata-Oplonti Villa di Poppea (a few stops after Ercolano Scavi). The 20- or 35-minute ride (depending on the train) from Naples costs 1.80€, from Sorrento 1.90€ for a 30-minute ride
By car, take the autostrada A3 Napoli-Salerno and exit at TORRE ANNUNZIATA SUD, Then follow the brown signs for SCAVI DI OPLONTI.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.