Last time there I did a private tour on 'Fat Cat'. It was a catamaran that took you out to snorkel and swim. I'm not sure they are still doing it, but I'll google them for you. It was great fun. I wrote a review of them on my blog.
I highly recommend the XCaret tour.. We done it and we all loved it! I cant wait until I get the chance to go back to Playa del Carmen because I would love to take that excursion again.
__________________ Past Cruises
Commodor Enchanted Isle of Capri-06.97
Royal Caribbean Sovereign OTS-4.16.07
Carnival Fantasy 4.28.08
Carnival Fantasy 10.27.08
Norwegian Pearl 3.13.11
Carnival Elation 11.14.11