Even if you only glimpse it from shore, spotting a pod of whales in the Pacific is one of Mexico's definitive experience. If you're lucky, you'll see a mama whale teach her young one the not-so-delicate art of breaching. Baja has gray whales in its waters from December to April; in particular, Laguna San Ignacio and Bahia Magdalena on the Pacific Coast seem to sing out a siren call to grays. They come in droves to give birth or mate. Sightings are also good between Puerto Vallarta and Manzanillo.
From the Forums: "Puerto Vallarta vs. Nuevo Vallarta?"