We were a small group of 13 and were delivered by air conditioned bus to the business, 10 minutes away. Promptly greeted, set up with mask, snorkel and fins, we listened to a short lesson regarding the rays, what we would be doing in the water, etc. The experience was wonderful. You will be swimming in deep water, over 20 feet, but have a live vest.
Quaint, touristy, small port area with typical shops selling souvenirs. I didn't go any farther than the main port area, so I cannot comment about areas covered by tours.