From Rome...by car:

On the GRA take the exit ''Appia'' and follow the indications for Velletri and near Genzano take a left for Nemi. Exit ''Appia'' from the GRA, follow the indications for Marino, Via dei Laghi, at 14 Km, take a left for Nemi.
Once arrived at Nemi park before the village and continue on foot following the characteristic medieval street as far as the historical centre, where we are situated.

...by train: 

The area is served by a dense railway network connected directly to Termini Station in Rome. There are 3 (three) railways lines which reach the area: the shortest is the Roma-Frascati line, that takes 25 minutes. More picturesque is the trip with the Roma-Albano line, which pass through Marino and Castel Gandolfo, with a view over the lake. The third railway line, Roma-Velletri, over looks the external side of the Volcano, with a view of the coast and the broad vineyards, the journey takes about 50 minutes.
Once arrived at the different stations, is possible to reach Nemi easily by taxi.

 ...by airplane:

The nearest airport to the Colline Romane is the Airport of Ciampino, situated on the Via Appia. From Ciampino Airport, is possible to reach Nemi in about 20 minutes by taxi.
From Fiumicino Airport to Nemi takes approximately 1 hour by taxi.