As on Santa Cruz, there are plenty of land- and water-based tour options on San Cristóbal. If you're visiting the island on your own, and you're not part of a guided tour, you'll probably want to check in with one of the many tour agencies -- there are a handful in Puerto Baquerizo Moreno, all located right around the downtown area. I recommend Chalo Tours, Española and Ignacio Hernández (tel. 05/2520-953); Turisgal, Avenida Charles Darwin and Teodoro Wolf (tel. 05/2521-041); or Galakiwi, Avenida Charles Darwin and Española (tel. 08/8102-663; www.galakiwi.com).
One of the most popular activities for travelers here is walking along the Malecón, a beautiful waterfront promenade, which was spiffed up considerably in 2006 and features several fountains, sitting areas, children's playgrounds, and even an enclosed saltwater swimming area, replete with two water slides (although it's more common to find sea lions enjoying this pool than people).
For a great panoramic view of the island, hire a taxi to take you to the Mirador de la Soledad, located a little bit above Progreso. Just below the lookout, you can visit La Iglesia de Soledad, a small church built into the rock here.
Centro de Interpretación (Interpretive Center) -- This humble little museum features exhibits and displays on the human, natural, and geological history of San Cristóbal and the Galápagos Islands. It's worth a visit. There are several rooms, all well laid out, with a mix of dioramas, artifacts, illustrations, and written explanations (in English and Spanish). I particularly like the relief model of the entire Galápagos Archipelago, which shows both the underwater and above-sea-level topography. The Interpretive Center (tel. 05/2520-358), on Avenida Alsacio Northia, Sector Playa Mann, is open daily from 7am to noon and 1 to 5pm. Admission is free, and it's about a 15-minute walk from downtown. Alternatively, if you take a taxi here, it should cost you just $1 (65p) each way.
El Progresso -- The only major road on the island connects the downtown port with El Progreso, the site of Manuel Cobo's infamous prison and work camp. If you visit, you can tour the ruins of the old farm house and see Cobo's grave. La Casa del Ceibo (tel. 05/2520-248) is a good place for a lunch break, and adventurous souls can inquire about the tree-house room for rent in the giant ceiba tree. Several buses a day leave downtown Puerto Baquerizo Moreno for El Progreso. The fare is just 20¢ (15p), and the ride takes about 10 minutes.
La Galapaguera de Cerro Colorado -- On the far southeastern end of the island is this protected area of dry forest, which is also a wild-tortoise habitat. A hike along the trails here is an excellent way to do some bird-watching and wildlife-viewing; you'll also have the opportunity to see one of the endemic San Cristóbal giant tortoises in their natural habitat. At the entrance is a small information center, and a corral with one captive tortoise, Genesis. There are several well-maintained trails, with some bilingual self-guided information plaques. If you don't come here as part of a guided tour, a round-trip taxi should cost you $25 to $30 (£17-£20). Tip: This is a relatively new reserve, and should not be confused with La Galapaguera, another protected habitat of giant tortoises, which is located on the far northeastern end of the island.
Laguna el Junco -- Formed in the crater of a dormant volcano, this is one of the few freshwater lakes in the Galápagos. It's only 240m (787 ft.) in diameter and barely 6m (20 ft.) deep. If you're lucky, you may observe the rare phenomenon of a giant frigate bird washing the salt off its wings in the freshwater lagoon.
La Lobería -- La Lobería, or Sea Lion Colony, is a pretty crescent-shaped beach with a large colony of sea lions. You will probably also see some blue-footed boobies and an endemic mockingbird here, as well as marine iguanas. This is a popular surf spot and therefore a bit rough for casual bathing, so if you go swimming, try to choose a calm section of the beach -- one that is also far from any territorial bull sea lion. La Lobería is about a 40-minute walk northwest of downtown. You can hire a taxi here for around $3 (£2).
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.