The Pacific waters here aren't nearly as clear as those in the Caribbean, but they are warm and nutrient-rich, which means they attract a variety of sea creatures. Many of the resorts rent or loan snorkeling equipment and have introductory dive courses at their pools.
The underwater preserve surrounding Los Arcos, a rock formation off Playa Mismaloya, is a popular spot for diving and snorkeling. The rocky bay at Quimixto, about 32 km (20 mi) south of PV and accessible only by boat, is a good snorkeling spot. Pangeros based in Boca, Mismaloya, Yelapa and elsewhere can take you to spots off the tourist trail.
On the north side, Punta Mita has the Marietas Islands, with lava tubes and caves and at least 10 good places to snorkel and dive, including spots for advanced divers. El Morro Islands, with their big fish lurking in the underwater pinnacles and caves, are also suitable for experienced divers.
Although it's fine all year long, June through September is the very best time for snorkeling and diving. In summer, the water is at its warmest and calmest and visibility is at its best—80 to 120 feet on a good day. You can spot gigantic manta rays, several species of eel, sea turtles, and many species of colorful fish. In winter's less favorable conditions, some luck will yield orca and humpback whale sightings, an awesome experience.
Chico's Dive Shop. This shop arranges PADI or NAUI certification, equipment rentals, and one- or two-tank dives. Trips to Los Arcos accommodate snorkelers ($40 per person) as well as those who want a one- or two-tank dive ($70 and $79, respectively). Book several days ahead for a night dive ($60 for one tank). You can also book tours with Vallarta Adventures from them. Paseo Díaz Ordáz 772, Centro, Puerto Vallarta, 48380. 322/222–1895 or 805/617 0121. www.chicos-diveshop.com..
Vallarta Undersea. This operation offers PADI dive courses; runs dive trips; and sells, rents, and repairs dive equipment. On Monday, Wednesday, Friday and Sunday tours are to Los Arcos National Park and another dive spot like Majahuitas, Colomitos or Mismaloya. Tuesday, Thursday and Saturday they visit Marietas Island National Park. Rates are 125 USD for certified divers, and snorkelers can tag along for 69 USD. Calle Proa, Local 22, Marina Vallarta, Puerto Vallarta, 48354. 322/209–0025 or 956/287-3832. www.vallartaundersea.com..