Most of the boats on the bay, whether fishing boats or tour boats, also run whale-watching tours (December-mid-March). Some boats are equipped with hydrophones for listening to the whales' songs and carry trained marine biologists; others use the usual crew and simply look for signs of cetaceans. The species you're most likely to see are humpback and killer whales (a gray whale occasionally); false killer whales; and bottlenose, spinner, and pantropic spotted dolphins (yup, dolphins are whales, too!).
Whale-watching is only available December through March. Prime breeding grounds are around the Marietas Islands. The larger boats leave from Marina Vallarta, but you can hire fishermen in villages like Corral del Risco, Mismaloya, Boca de Tomatlán, Yelapa, Las Animas, Barra de Navidad, and Tenacatita for less formal, more intimate trips. The larger boats are more likely to have radio equipment useful for communicating with others about the location of whale pods. Some outfitters offer a discount if you sign up online.
Ecotours. After a brief lecture about cetacean ecosystems, you'll board a boat equipped with hydrophones at Punta Mita for a three-hour tour. Tours are daily in season (mid-December to mid-March) and cost $75. Ignacio L. Vallarta 243, Col. E. Zapata, Puerto Vallarta, 48350. 322/223–3130 or 322/222–6606. www.ecotoursvallarta.com..
Sociedad Cooperativa Corral del Risco. Two hours of whale-watching or snorkeling around the Marietas Islands, for up to 10 people, costs $114. Anyone older than 6 but younger than 60 also pays $2 for a wristband allowing entrance to the Marietas, a national aquatic park. You search until whales are spotted, and then have a half-hour of viewing time before returning to dry land. Av. El Anclote 1, Manz. 17, Corral del Risco, 63734. 329/291–6298. www.puntamitacharters.com..