Given that Puerto Rico is an island and not reachable via land or bridge from mainland USA, the vast majority of visitors fly in to Luis Muñoz Marín International Airport
, located just inside the popular Isla Verde/Carolina area. Built in 1995, it's now the Caribbean hub for many major airlines, including American. For a comparatively small airport, it's incredibly busy: over 4 million people fly in and out annually. Most major hotels have their own shuttle buses that run back and forth to the airport, and there are public buses that travel from the airport to Old San Juan, Isla Verde, Condado and more. Major car rental companies can also be found at the airport.
Nothing's easier than arriving in Puerto Rico via boat, whether you sail in aboard your own yacht, or arrive on a hulking cruise ship at the Old San Juan port. There are several working marinas around town, and some of the biggest hotels also have their own marinas with docking slips available for rent. San Juan Bay Marina is closest to Old San Juan, and another big one, Cangrejos Yacht Club, is closer to Isla Verde. For cruise ships, nearly all docking is in Old San Juan, at the main port there. You can also get here by ferry from the Dominican Republic and the US Virgin Islands.
You're pretty much on your own when it comes to San Juan's public transportation. Yes, there's a small-scale metro of sorts called Tren Urbano (.75 cents) but it's unlikely to be of use to you, since it is only connected to the outer suburbs and San Juan's business district, Hato Rey. There are plans to expand it to Old San Juan and other areas, but who knows when (if) it will happen. The Metropolitan Bus Authority takes care of the "guagua" (that's wah-wah) buses that run sporadically and inefficiently around San Juan. You'll know you are at a bus stop when you see a sign saying "Parada." The most useful route for visitors goes from Old San Juan to downtown Santurce, Condado, then down Isla Verde's oceanfront road to all the major hotels. The main challenge with the buses is knowing when they're going to come; no real schedule exists. Within Old San Juan, there's a free trolley service that zips along the streets.
Here’s the deal: San Juan taxis have meters, but the drivers absolutely hate using them. If you can convince a driver to turn it on and use it, the meters start with a $2 fee, then $1.90 per mile. There’s also a surcharge of .15 cents for wait time. But it’s rare to get a metered fare. Usually you need to bargain a flat fee with your driver before he takes off. There are set fares for well-traveled routes: $22 from Old San Juan to Isla Verde, for example, or $12 from the airport to Isla Verde or $15 to Condado, and $22 to $25 from the airport to Old San Juan. Taxis are frequently found at the end of Calle Fortaleza in Old San Juan, and around major hotels. If you need one in a hurry, don’t stand on a dark street corner waiting (muggings do occur in San Juan). Head to a restaurant or hotel and call one to pick you up.
Parking is a challenge in San Juan, and in particular in the one-way streets and narrow alleys of Old San Juan. There are parking garages scattered around the city that run anywhere from $15 for the day to $2 an hour. Your biggest concern won’t be traffic (although there is a lot at rush hour), but finding a safe place to leave the car overnight. Crime is a factor on the island, and cars (especially rentals) left on dark streets are routinely broken into. If your hotel doesn’t have a parking garage, try to find one nearby.