As an alternative: Isla Holbox, Mexico
This car-free island 40 miles northwest of Cancún offers 26 miles of mangroves and beaches in the vast Yum Balam biosphere reserve. It’s separated from Mexico’s mainland by a shallow lagoon where flamingos and pelicans converge. Get there by flying into Cancún, driving two hours to Chiquila, then taking a 30-minute ferry ride. You’ll find a range of accommodations, from cabanas at Hostel Ida y Vuelta (holboxhostel.com; from $26 ) to four-star hotels such as the Villas HM Paraiso del Mar (hmhotels.net; from $92). Beach bums can sunbathe; adventurers can snorkel with gentle whale sharks, the world’s largest fish at about 41,000 pounds, from May to September.
Pelicans gather by Yalahau lagoon on Isla Holbox