Tulum archaeological site
Muyil archaeological site
Grand Cenote
Cenote Calaveras
Dos Ojos Cenote - 100 pesos for entrance only good if you bring your own equipment and are ready to walk 3km to the cenote. 300 pesos for a guide, ride to the cenote, snorkel equipment, lamp, and wetsuit if you want. Set aside around 2 or 3 hours total.
Sian Ka'an Biosphere - The reserve features acres upon acres of pristine mangrove swamp and wetlands. Just past the information center pull into the dirt lot on the left and walk out to the beach. There are a few fishermen that dock here and are willing to take you on a tour that is much cheaper than the organized tours offered in the area. The fishermen will take you on an hour to two hour boat tour of the reserve anyt time of day. Near sunset is a great option. They will often work for hire for 100 to 200 pesos or 10 to 20USD.
Coba ruins - Be sure to visit the Coba ruins. They are not in as pristine shape as the Tulum Ruins, however they feature "el castillo" the tallest of the Mayan ruins that juts up above the treetops in the jungle. You can still climb el castillo in Coba and the sight from the top is spectacular. A fun and efficient way of exploring the ruins is renting a bike $35 pesos; just go to the rental place inside the ruins. You can also rent bikes to get around Coba. Coba is only a 30 minute drive west of tulum on the main road off 307. Just follow the signs to Coba!
