Luis Muñoz Marín International Airport (SJU) is the main entry point — the largest airport in the Caribbean, with direct flights from most major US cities, several European hubs (Madrid, Frankfurt), and other Caribbean and Latin American destinations. It is in Carolina, about 16 km east of Old San Juan and 10 km from Isla Verde.
Cruise ships dock at the terminals on the south side of Old San Juan; the historic city is a five-minute walk from the piers, which is one of the reasons it gets so busy on cruise days (typically Tuesday through Saturday).
Ferries from Fajardo on the east coast serve Vieques and Culebra. A small commuter ferry, the AcuaExpreso, runs across San Juan Bay between Old San Juan and Cataño (the Bacardí distillery side) every half hour during the day for under a dollar.
As US territory, Puerto Rico requires no passport for US citizens (a driver's license is enough). Other travellers need the same documents as for entry to the United States, including ESTA for visa-waiver countries.