We stayed in Mayan Palace about a month ago for a week. We got up and went to Playa Del Carmen every day but didn't see any dive shops local to the Mayan Palace. The Mayan is a really nice place but it's a bit removed from the local stuff.
Go to playa and you'll have more good dive shops than you can shake a stick at. If you rent a car you are good-to-go, we didn't have a car we just took the white shuttle buses that go by every few minutes. They were 10 or 20 peso's per person each way so they are really inexpensive. It's about a 15-20 minute ride from the Mayan into Playa.
We also go suckered into a timeshare presentation (well, suckered isnt' the right word, we went in knowing it was a timeshare deal but instead of a small room we got the whole suite for a week by attending it so we just suffered through it and then spent two-three hours saying "no thanks, not thanks, we already have one, no thanks, I know it's a good deal, I know this price will never be this low again, yes I'm sober, no thanks, I know it's a good deal, no I don't want to buy one at half the price, etc.... )
I used both Yucatec divers and Studio Blue while I was there. Yucatec was nice but Studio Blue was AWESOME. They were very accomodating of my pregnant wife, I went on one dive out at Cozumel with them and when they heard my pregnant wife was sad she couldn't dive with them they offered to let me go with one of the "Discover Scuba" classes at Paraiso Reef where I could dive and she could snorkel along with us so she could go too. Then they took her on a sweet snorkeling trip while I went on a wreck dive.
I think their website is
www.cozumel-diving.net/studio-blue
you can also see pictures from some of our dives at
www.phantomdivers.com
They were totally great. They have a store in Playa del Carmen and also one out at Cozumel.
The Mayan is great but make sure you have some mosquito dope, we were in Cancun for two days and no bites but in the Riviera Maya I got *hammered* by mosquitos. I'm 6'5" and a hair over 300 lbs so I am a traveling buffet for skeeters and they took full effect.
Have fun down there, we had a blast and want to go back in two years so my wife can go diving too. She was pretty mad I got to go and she didn't.
matt