If you are intent appreciating the amazing ruins, cenotes, and beaches in the Cancun area, I recommend you hop the ADO bus for $6 - $10 and stay a few nights in Tulum. There's not much there, but you are right by the attractions and can go before the throngs of people inundate the site.
*my Coba advice:
Coba is 30 min away from Tulum. The first bus from Tulum does not depart until 9am. And there is only ONE bus back to Tulum at 3pm. You do not need more than 2 hours there. Trust me. (Unless you are herding a family... Then I'd factor in another hour). I was up the pyramid in 5...10 min, tops. You do NOT need to waste your money booking a group tour from your hotel. Entrance is about 65 pesos - less than $6. You can book a guide once you're there. For the same price as one of those tours, you can arrange a deal ahead of time with a taxi from Tulum and you can be the first one there and leave when you're ready. The driver will also throw in an hour to visit a few local cenotes. Waaaay better than a large group tour. I snapped my photos without another soul present. As I was leaving the pyramid, the tour groups were arriving, and I overheard the guide tell his group that they had 10 minutes and then the group was moving on. Are you really going to pay over $100 for TEN minutes? Chances are, if you're reading this review, you are already researching your vacation. Don't ever pay for tours when you can do something yourself on your own schedule.
Of course, if you're a blonde, attractive, and ever-so-humble female who speaks Spanish, like moi, you can get some really great deals! Lol.
Spanish or no, research is your best investment.
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