[Wryknow]

Well, I have been to the area a number of times and dove and snorkelled quite a bit. My own personal opinion is that some of the most fun trips have been snorkelling and if you are not a certified diver I would consider buying a good set of snorkelling equipment and give that a try first. With a little practice you can easily breath-hold dive to 20-30 feet and the reefs in that area are very good in shallow water.

On the mainland side (Playa/Tulum/Cancun) the water conditions vary a lot day by day so you may not be able to dive when you plan to. If there is a lot of current then the visibility gets bad and there can be strong undertows in some areas so its best to go with a pro if you can. There are tons of little dive/snorkel outfits that will run you out to a reef and let you snorkel (or dive) for a minimal fee and when I'm in the area I just find one or two close to the hotel and walk over in the morning to check the water conditions and decide if I want to book a trip.

If you really want to go to a primo dive spot then take the ferry over to Cozumel. It's about a 30 minute trip from Playa and the conditions on Cozumel are much calmer and more predictable because the reefs are on the lee side of the island. Palancar gardens is my favorite dive spot there. You may also want to check out one of the fresh water c'enotes. They are pretty neet too.