It’s possible to hit San Juan’s highlights  in a single long weekend, but it’s equally possible to spend a whole month here and not see all the city has to offer.
Old San Juan  is the cultural center of Puerto Rico . The 500-year-old city is filled with many historic buildings, Spanish forts, museums, restaurants, bars, shops, and ship docks. Beach access is very limited in Old San Juan, and a thick concentration of tourists can be found here, especially on days the cruise ships dock. But its charm is undeniable.
Among Old San Juan’s many must-see sites are the city’s two Spanish fortresses, Castillo de San Felipe del Morro  and Castillo de San Cristóbal ; the significant religious sites of Catedral de San Juan Bautista  and Capilla del Cristo ; and two terrific museums, Museo de Las Americas  and La Casa de Libro .
The best way to see Old San Juan is by foot. The roads are drivable, but they’re narrow and one-way, and only residents’ automobiles are permitted in at night. If walking gets to be too much, there is a free trolley service that runs through the southern half of the city where most of the shops are. The main public bus terminal is near the cruise-ship piers on Calle de Marina, just below Plaza de Colón  in Old San Juan, and there are taxi stands in front of most plazas and hotels.
Condado is considered San Juan’s tourist district, although Old San Juan and Isla Verde could qualify for the same designation. The community, which runs along a stretch of beach between Old San Juan and Isla Verde, is undergoing a dramatic transformation. Once the height of glamour, this strip of flashy resorts and hotels fell onto hard times during the recession of the early 1980s, and many hotels closed.
But things are on the upswing. Several cranes hang over Avenida Ashford as old buildings are undergoing renovation and new construction is under way. New parks have blossomed, giving passersby access to the Atlantic Ocean and a great place to relax and people-watch.
Aside from its beaches and hotels, Condado is home to some excellent restaurants and casinos, and it is the best place to go for upscale shopping  at places such as Louis Vuitton and Cartier. Taxis and public buses traverse the area frequently, and its wide sidewalks and browse-friendly businesses make it an excellent place for pedestrians.
Miramar, an upscale residential area overlooking Laguna del Condado, has recently been designated a historic district and is scheduled for millions of dollars in improvements.
Isla Verde is renowned for its long, wide beaches, its luxury resorts, and some pretty spectacular nightclubs and casinos. When you’re catching some rays on the beach or partying the night away in a glitzy hot spot, it can feel as glamorous as a mini–South Beach. Unfortunately, the only way to actually see Isla Verde’s gorgeous coast is from one of the high-rise hotels and condominiums that line every inch of the way. And the traffic-choked main thoroughfare, Avenida Isla Verde, is a jumble of fast-food restaurants, pizzerias, souvenir shops, tattoo parlors, condom shops, and so on. The community is also home to the Aeropuerto Internacional Luis Muñoz Marín.
The best way to enjoy Isla Verde is to ensconce oneself in one of the community’s cushy seaside resorts and stay there.
Wedged between Condado and Isla Verde is a tiny oasis of quiet gentility called Ocean Park. Primarily a gated residential neighborhood, the ocean-side community has only a handful of restaurants, and shopping is nonexistent. But there are several very nice guesthouses right on the beach, and they’re excellent places to stay if you want a refuge from busy urban settings and crowded tourist attractions. There’s also an excellent stretch of well-maintained public beach with parking.
Just a few blocks inland from Condado is Santurce, a congested conglomeration of small shops and businesses that cater to residents of the island. Tourists are advised to take precautions when visiting the area at night as it has a high rate of street crime. Nevertheless, it is home to the superb Museo de Arte de Puerto Rico  and several popular nightclubs .
Outside San Juan’s popular tourist areas are communities central to the lives of San Juan residents. Hato Rey is the city’s business and financial district, chock-full of banks and restaurants that cater to businessmen and women. It’s connected by the new 10-mile Tren Urbano metro system to Río Piedras, home of the University of Puerto Rico and El Jardín Botánico , and the residential area of Bayamón, home of Parque de las Ciencias Luis A. Ferre  science park.
Several spectacular day trips are less than an hour’s drive east of San Juan , the most popular being El Yunque Caribbean National Forest , the rain forest, and Balneario La Monserrate , considered one of Puerto Rico’s most beautiful beaches.