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Puerto Aventuras. PA is about half way between PDC and Tulum, so easy access to many of the tourist destinations, plus there is an on-site dolphin discovery.
Ahh - you've caught wind of Puerto Aventuras (and want to know more)... lucky you! :) Residents here are keen to keep this place a secret. ;) But seeing that you made it this far... I'll share my local knowledge
www.playadelcarmen.com
We started going there in 2004 and it became our staple (easy flight from DFW, and great relationship with dive shop) until COVID.
You can rent condos in the gated community, and there are multiple restaurants within the compound.
There's also a Chedraui grocery store right across the highway which is about a $5 cab ride each way (along with a farmer's market inside the compound a couple of times a week).
It is one of the few places along the Riviera Maya where, for ocean diving, you board the boat from a dock in a marina.
The ocean reefs are very healthy with good fish populations, maybe not the structure or drift diving you would expect in Cozumel, but we enjoyed the diving.
Most of the dive shops in PA also offer cenote diving.