The water is clear up to 60 feet, and there's plenty to see beneath the
waves. Susan Dearing, one of the most experienced dive operators on Mexico's
Pacific coast, and the owner of Underworld Scuba (Plaza Pacífico, Santiago;
52-314/333-0642; two-hour snorkeling trips from $38, including gear;
three-hour dives from $76), organizes excursions to the best spots. The
company also leads half-day hikes ($55, including lunch) to a swimming hole
at the base of a 100-foot waterfall and to the cloud forest in the foothills
of the Sierra Madre.