No snuba on the Reniassance island. There is snorkeling and scuba diving. The diving can be done from the beach out to the sonesta airplanes or be done by red sail boat. At the island you can rent a raft, kayak, snorkel and dive equipment. I've been going to that island for 10 years now. I love it!
I have bad sinuses. About 12 years ago on vacation in Jamaica I decided I wanted to give scuba a shot.
Talked to the instructors at the resort and they equipped me with the gear and took me into the swimming pool to see if I would be able to clear my ears.
To me it is more a technique to be mastered than a matter of black and white being able to do it or not do it.
Your discover scuba course would be in about 20 feet of water.
Like Andrea said, if you are prone to congestion in the first place, simply taking a decongestant beforehand, dry/drain you out also aids you in making sure there are no fluids there in the first place.
My then 10 yo doing her pool "check out" with her "mini" gear.
we had a blast on the 3-6 jolly pirate tour. would do it again in a heartbeat.
deplams atv tour was just ok. my 13 year old and i had fun but just like the rest of the depalm tours we did we felt rushed and it didn't take us to the natural pool. i recommend renting an atv or jeep and getting a good map and seeing the sights on your own and at your own pace.