Do I need a passport?
No. When you travel to Puerto Rico, it's like going anywhere within the U.S. All you need is a driver’s license or other valid form of photo ID. In fact, Puerto Rico is one of only two destinations in the Caribbean (the other is the U.S. Virgin Islands) that do not require U.S. citizens to carry a passport.
Will my cell phone work?
Yes, your cell phone should work in San Juan and most of the cities.
Will I need to convert money?
No. The dollar is the only currency you’ll need.
Do I need to know Spanish?
Both Spanish and English are the official languages of Puerto Rico. In the big cities and in the islands of Vieques and Culebra, you can get by without a word of Spanish. The people who work in the tourist trade—waiters, shopkeepers, guides, etc.—usually speak fluent English. The police are another issue: it’s not easy to find an English speaking cop. The farther away you move into the less urban interior of the island, the more you’ll need to have some command of the language.
Should I rent a car?
Most major national car rental companies have offices on the island, along with many local agencies. The highways are well paved and generally easy to navigate. But before you book your rental, consider the following:
Cost
In general, you’ll pay a bit more than the average price of a rental in the U.S. (try the local competition for better rates). You may also be required to pay liability insurance: credit cards that offer auto coverage in the continental U.S. don’t always extend that coverage to Puerto Rico, and your insurance company may not cover the island.
What do you want to do?
If you plan to explore the island in depth, you’ll definitely need a car. Also, people traveling to Vieques and Culebra should consider renting a jeep or car once they get there. But, if you are sticking around San Juan, forget the rental. Old San Juan is a walking city, and you can easily get around the city in a taxi or a bus. Parking and traffic can be a nightmare in the city, and a rental might be more trouble than it's worth.
Numeric Confusion
For reasons best known to themselves, Puerto Ricans use both miles and kilometers: distances are posted in kilometers, while speed limits are shown in miles. Also, gas is sold in liters, not gallons.
Traffic
Puerto Rican motorists are in a great, careening hurry to get places, and the orderly laws of road conduct are more loose guidelines than strict rules here. This makes for a sometimes harrowing experience for timid drivers. If aggressive drivers scare you, a rental might not be your thing.