In addition to being a phenomenal place to spot fauna on hikes and boat rides, the Galápagos Islands are a world-class scuba-diving destination. Unlike popular areas such as the South Pacific and Caribbean, the Galápagos don't have coral reefs, because the water is too cold. They do have a lot of marine life, including manta rays, sea lions, penguins, sea turtles, iguanas, at least five species of sharks, and hundreds of other fish species, many of them endemic to the archipelago. Galápagos cruises generally offer snorkeling or scuba diving; keep in mind that the water is chilly and most people need a wet suit. A handful of boats catering to experienced divers offer cruises that include any of 30 dive sites over the course of a 1 to 2 weeks. Two to four daily dives are complemented with island excursions. All divers must pay the one-time, $100 (£67) national park admission fee and port fees.

The best months for diving are November to April, when seas are calmer and the water is less cold: 18° to 23°C (64°-73° F). However, even then, many dive sites experience strong currents, surges of cold water that can get as low as 10°C (50°F), and visibility that can get as low as 3m (10 ft.), though it averages 6 to 24m (20-79 ft.). Many of the dives are relatively deep. Night dives are prohibited in the Galápagos. Divers need to prove that they are experienced and have been diving recently in order to join trips. They will also need to use a full wet suit, often with hood. Because of the nature of the diving here, I recommend taking a dive boat with Nitrox facilities. If you aren't already Nitrox certified, you can take the course onboard and dive with Nitrox tanks during the trip. Nitrox will allow you increased time below the surface, an important consideration with these predominantly deep dives.

Various ships offer dive cruises to the northern islands that include comfortable accommodations, good food, and creature comforts. The best and most challenging dive spots are located around the archipelago's northern islands, especially Wolf Island and Darwin Island, but because the main attractions are on the southern islands, excursions that combine divers with nondivers tend to stay in the south.

A less-expensive option is to stay on Santa Cruz or on San Cristóbal and take day trips with a local dive operator. Though the best dive spots are too far north to reach on anything other than a liveaboard ship, there are dozens of excellent dive spots within a 20- to 90-minute boat trip from Santa Cruz, including Gordon's Rocks, where schools of hammerhead sharks sometimes congregate. The conditions in the south are also less demanding, and local dive schools offer basic certification and resort dives for novices.

Though the Galápagos has Ecuador's best diving, the Pacific coast also has its share of dive spots, the best of which is around Isla de la Plata, an offshore island about 2 hours by boat from Puerto López. Dubbed the "poor man's Galápagos," Isla de la Plata has many of the same fish, including white-tipped sharks and manta rays, as well as plentiful birdlife. From June to October, dive trips to the island can be complemented with whale-watching.

Diving Boats & Operators

Aggressor Fleet Limited (tel. 800/348-2628 in the U.S. and Canada, or 04/2681-950; www.aggressor.com) runs 1-week cruises for 14 divers to the islands' best spots on its two identical 30m (98-ft.) boats: the Galápagos Aggressor I and II. Boats include Nitrox facilities, film developing, and underwater-camera rental. A 1-week trip costs $4,095 to $4,295 (£2,730-£2,863) plus airfare, and the $100 (£67) national park and $75 (£50) port fees.

Exploramar Diving (tel. 02/2564-342 or 05/2300-123; www.exploradiving.com), an Ecuadorean company with dive centers on Santa Cruz Island and in Puerto López, Manabí, offers a selection of diving packages for the Galápagos and Isla de la Plata, as well as PADI certification courses.

Galápagos Sub-Aqua (tel. 05/2526-633; www.galapagos-sub-aqua.com), an Ecuadorean company in Puerto Ayora, is the archipelago's oldest dive center. They offer PADI certification courses, land-based packages, and cruises custom-designed to divers' experience levels.

Machalilla Tours (tel. 05/2300-234 or 09/6109-185; machalillatours@yahoo.com) is an excellent local operator based out of Puerto López. They offer diving trips to sites around Isla de la Plata, as well as off the coast of Manabí.

M/S Sky Dancer (tel. 800/932-6237 in the U.S. and Canada, or 04/2207-177; www.peterhughes.com), part of the international Peter Hughes Diving fleet, is a 30m (98-ft.) vessel with eight staterooms. Top-notch dive masters, food, and Nitrox facilities make this the second-best diving option in the Galápagos, after the Aggressor boats . A 1-week cruise with several daily dives and meals and beverages costs $4,095 to $4,795 (£2,730-£3,197) per person, double occupancy, plus airfare, $100 (£67) national park admission, and transfers.

Scuba Iguana (tel. 05/2526-497; www.scubaiguana.com) is an excellent operator, offering an array of day trips out of Puerto Ayora, as well as diving certification courses.

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.