San Juan has some of the best municipal beaches this side of Rio de Janeiro. Starting a mile or so east of the old town, you can go from rustic to swanky and back to rustic all in the space of 7.5 miles.

San Juan's Urban Waterways

While it's easy to focus on the beautiful waters off San Juan's beaches, the city also has some remarkable waters just inland. Estuaries back up most of the coastal lands and surround the airport. The mangroves here are home to over 100 species of birds, 300 types of plants, dozens of different kinds of fish and even the odd manatee. Unfortunately, there's also a lot of trash that's typical of urban waterways. Recently, groups have begun cleaning up these sprawling lagoons and waterways, and while it's thought that a real clean-up would cost an unaffordable $600 million, locals realize that you have to start somewhere.

The following community groups offer ways to get out on these waters, which are truly the heart of the city. Away from the high rises and traffic, you discover a serene side to San Juan.

Excursiones Eco Offers guided trips through the Caño de Martín Peña, a 3.5-mile tidal channel that connects the Bahía de San Juan with the Laguna San José. Passengers explore its mangrove forest and bird habitat while learning about its history and the current struggles of the low-income neighborhoods surrounding it. Walking tours that visit these underserved former squatter communities, which now house some 27,000 people, are also on offer.

Expediciones Península Has well-organized weekend tours of the main lagoons, focusing on wildlife and the culture of the people living around the waters. Tours last up to three hours and combine a boat ride with walking. Call to reserve and confirm times and meeting point.

Corporación Piñones Se Integra A community-based nonprofit working to improve life in Puerto Rico’s poorer barrios, as well as to protect the urban waterways. Headquartered in the Centro Cultural Ecoturístico de Piñones, the group rents out kayaks for self-guided explorations of the adjacent Laguna Torrecilla, a beautiful mangrove-ringed body of water just east of the airport.

Visiting the San Juan National Historic Site

A visit to the two megastars of the San Juan National Historic Site, El Morro and Fuerte San Cristóbal, can be made even more rewarding with a just bit of planning.

Visitor centers Each fort has a small and useful visitor center where you can learn more about the structures and buy books that delve deeper into their history.

Joint admission Tickets are good for both forts and are valid for seven days. If you can, try to visit each on a different day so that all those walls don't start looking the same.

Orientation talks There are short, highly useful free introductory talks every hour at each fort, provided there are rangers available. Ask when you buy your ticket.

Tunnel tours Hour-long free guided tours roam the tunnels at Fuerte San Cristóbal every Saturday (English) and Sunday (Spanish) at 10:30am and 12:30pm. Come at least half an hour beforehand (or earlier) and add your name to the sign-up list. Guides walk you through three of the fort’s tunnels, including one that’s otherwise closed to the public.

Outworks walks Hour-long free guided tours of the fortifications show how Fuerte San Cristóbal remained impregnable. The walks are held every Saturday (Spanish) and Sunday (English) at 2:30pm. Sign up at least half an hour beforehand (or earlier).

El Morro life On the third Sunday each month, guides and recreators give an idea of what life was like for a soldier in El Morro during the 18th century when drills and duty dominated. While the recreations don't capture the smells of a time when bathing was a luxury, they do show what happens when you explode the black powder used in cannons.