Sperlonga can be reached by road. From Rome, take the via Appia or the via Pontina past Terracina, then follow the signs to Sperlonga along the via Flacca. From Naples, go to Formia, Gaeta, and again with the via Flacca to Sperlonga. An alternative way is to go along the Appian way (via Appia) between Terracina and Formia, and take the smaller road to Sperlonga from Itri.
Sperlonga can be reached by train. One of two major train lines between Rome and Naples (Roma-Napoli via Formia) stops in Fondi. The station is called Fondi-Sperlonga, and local trains stop there. When going North to South, the last station before Fondi is called Monte San Biagio. When going South to North, the last station before Fondi is Formia. From the station of Fondi, a taxi to Sperlonga should be around 20 Euro. A bus service (1 €) from the train station to Sperlonga is also available once an hour (during summer) and every second hour (during winter). The bus timetable is roughly coordinated with the arrivals and departures of the trains. The distance from the train station to Sperlonga is about 12km by road.
It is also possible to take a bus to Sperlonga from various surrounding locations, including Terracina, Fondi, and Formia/Gaeta.
Sperlonga is fairly small, and getting around by foot is quite reasonable if one doesn't mind climbing lots of steps. The are two centers. On one hand there's the center on the top of the old town where you can enjoy magnificent views over the bay. The old town is closed to traffic. The other center is along the beach.
It is fairly easy to drive around Sperlonga. It is often hard to park around Sperlonga in the peak season. At other times, there are many parking lots near the old town.
There is a bus service within Sperlonga.
Sperlonga was built as a medieval fortress on a hill overlooking the Gulf of Gaeta. It is very picturesque, with narrow paved streets, many made up mostly of steps, and houses nearby with bridges connecting them. The town has been more than once attacked and taken by moorish pirates, most famously by Khayr al-Din (Barbarossa) in 1534.
The two beaches on the two sides of the old town of Sperlonga are quite popular. One beach stretches all the way to Terracina, 18km away. The other beach ends at a cave known as the "Grotta di Tiberio", "Grotto of Tiberius" or "Cave of Tiberius". The emperor Tiberius was known to have a villa in the area. The cave has yielded a number of marble sculptures which are housed in the museum that is along the via Flacca not far from the cave, a little South of the town.
The main draw of Sperlonga is the beach. The beaches are good for swimming, and in summer the sea is generally calm.
Sperlonga is nice to visit, though there are few specific landmarks ---- the town itself is the landmark.
Nightlife is available in Sperlonga, including hanging out on the main square of the old town and the road leading to it, a good selection of restaurants, and a selection of night clubs.
The archeological museum of Sperlonga can be found along the Via Flacca, south of town. It sits on a villa built by Emperor Tiberius. It houses several sculptures and artifacts from the villa. The ticket for the museum includes entrance to the Grotto di Tiberius or Cave of Tiberius.
Along the via Flacca it is possible to find shacks selling "Mozzarella di Bufala", traditional Mozzarella cheese made with Water Buffalo milk. The water buffalos are traditional in the area north of Terracina, the former Pontine swamps, as well as in the surroundings of Fondi, which used to be swampy.
Many restaurants in Sperlonga serve seafood, as well as other foods including pizza (being relatively close to Naples, the pizza is fairly authentic). Most of the restaurants are situated either in the center of the old town or along the street next to the beach.
Sperlonga also benefits from being near the agricultural area centered around Fondi, so many local fruits and vegetables are very fresh. There is usually a farmers' market in the main square of the old town.
Da Filippo, in the lower town (near the beginning of the old town), makes ice creams and other pastries.
There is a drive-in campground inland from the beach where the Grotta di Tiberio is. Camping on the beach is not permitted.
There are many other interesting towns and landmarks within one hour's driving distance of Sperlonga. In particular, the old town and harbor of Gaeta, the old city of Fondi (of which not much is left, beyond a spectacular city gate), the temple of Jupiter Anxur in Terracina, the tomb of Cicero near Formia.
The via Flacca between Sperlonga and Gaeta runs along cliffs high above the sea, and also has many tunnels. On most of the cliffs it is still possible to find remains of the old roman via Flacca, and to follow them on foot. One section includes a tunnel that was built by enlarging a cave, and which is only accessible on foot. This road also leads to many small beaches, often with a restaurant or other facility. Many of the cliffs also have ruins of old watchtowers.