Big Cancun tour operators like AquaWorld (www.aquaworld.com.mx) offer loads of easily accessible dolphin "experiences," where guests get the chance to meet and swim with captive dolphins. Better, though, to head to Isla Mujeres for the day and explore Garrafon Natural Reef Park (www.garrafon.com), an eco enclave with activities including dolphin encounters, snorkeling, ziplining, or just lazing on the beach.