You have two options for travel to the island—airplane or cruise ship. The cruise ships stop at San Juan, which is a must-see city destination (though to really experience the life of the island, you must travel beyond the island’s capital). SJU is the biggest and most modern airport in the Caribbean. If you are flying here from another Caribbean island, Liat may be your best option. From the East Coast of the U.S. mainland, try Jetblue, Spirit, or Southwest. From everywhere else, there is Delta, American, or United. A perk for U.S. citizens: This is a passport-free destination!
For daytime travel, public transit services do exist within individual cities, but they are limited. Taxis are clean and reliable—look for white cabs with Taxi Turístico on the front doors. The shared cab (public) system goes around the island for a small fare, but it takes an extended amount of time due to the numerous stops along the way. Most travelers choose to rent a car for the duration of their stay. The currency is US dollars, and the road system resembles that of the mainland. There are two exceptions: Distances are measured in kilometers, while speed is measured in miles per hour. Additionally, gas is represented in liters, and prices are competitive with those on the mainland. One roadway custom worth mentioning is that police and ambulances drive with their lights flashing, but unless they also blast their sirens, there's no need to pull over or move aside.