Divers who know this trio of tiny uninhabited islands say that its kelp beds are as rich with life as the Channel Islands were 75 years ago. Purple hydrocoral grow on underwater pinnacles, abalone and lobster hide in rocky crevices, and sightings of 9- to 18-kilogram yellowtail are common. Thriving populations of California sea lions, giant elephant seals, and Guadalupe fur seals provide even more fun.

Islas Benito del Este, Centro, and Oeste are located about 80 kilometers west of Baja and about 450 kilometers south of San Diego—within reach of California-based liveaboard services. Horizon Charters (www.horizoncharters.com) occasionally runs an eight-day, seven-night dive trip to these islands. Boats depart from San Diego and stop at Isla San Martin on the way south.

Bilingual marine biologist Jose Sanchez-Pacheco offers a variety of guided trips through Cedros Outdoor Adventures (tel. 646/154-3085, cell tel. 646/193-2031, U.S. tel. 619/793-5419, www.cedrosoutdooradventures.com), which is based in San Ysidro, California. Package trips include ecotours to Isla Cedros and the Islas San Benito (four days/three nights US$980) and sportfishing trips to Islas Cedros, San Benito, and Natividad (four days/three nights US$1,350). Prices include transportation from San Ysidro, California, as well as accommodations and meals.