Located a short speedboat ride from Punta Mita and Puerto Vallarta, the small archipelago of Islas Marietas was designated a national park in 2005 and a UNESCO Biosphere Reserve in 2008. Nonetheless, overtourism damaged the site. The otherworldly Playa Escondida, the “Hidden Beach” where everyone wanted a selfie, suffered in particular, with upward of 2,000 visitors a day leaving trash and damaging the coral reef. Visitor numbers are now carefully restricted. Only certain tour operators can visit the archipelago at all, and a mere 116 people per day can visit the Hidden Beach, which is closed entirely on Monday and Tuesday.

Imanta Punta de Mita booked a private excursion for us, including coveted permits to the Hidden Beach. A guide and captain affiliated with the Mictlan Surf School took us out in a small but speedy boat. En route, we paused to watch a juvenile humpback and its mother. The former breached five or six times. The craggy islands of Marietas are a bird sanctuary, and we spotted pelicans and blue-footed boobies.