Kate here, I highly recommend making a day trip to the historic Chichen Itza! And if you're coming this far, you must see Cenote Ik Kil and Cenote Suytum.
Sunset Sailing Cruise in the Riviera Maya
The Grand Mayan at Vidanta Riviera Maya, Carretera Federal Cancun-Playa del Carmen Km. 48, Playa del Carmen, 77710, Mexico