I've stayed at this resort several times, I recommend "Akumal Dive Shop".
Akumal is about 5-7 minutes south of the resort.
They have lockers available to leave your gear for your convenience getting back and forth. If your traveling companions enjoy snorkeling, Akumal bay is spectacular with a large variety of sea life including turtles, rays, squid, barracuda, and a large variety of fish. They could make a day of it there quite easilly as there are serval beachfront restaurant/bars and some shopping as well while you get some dives in. I have done just this with my family.
If you would like any advise drop me a PM with your contact info and I'd be happy to help...
I see Blue Life has responded and is on location, I don't believe they were onsite last time I was there about 3yrs ago...