We liked Garrafon cuz theres ziplines, snorkling, food and bar all-inclusive. And at 1pm you can buy a half-day pass, which is enuf - unless u want to sit in a hammock for a few hours - which lots were doing. We didn't do dolphins but the dolphin tank's the biggest in Mexico, so if I was going for the dolphins, I'd go there.
kimbb, you should do a few cenotes in your week there, cuz theyre quite exciting....doesn't matter where; the ones I've seen are all good
