We did it and had a great time.

Myself DH and 2 DS's 7 and 9 years.
Here is my past post.
The adventure starts with a 20 min boat ride to the island. They welcome you to island and will announce when it's time for you to snorkel with the stingrays. You can snorkel with the stingrays for about an hour I'm guessing. I was there for about 30 mins, others stayed longer.
At around 12ish they let you know it's time for you to have lunch (burgers, hotdogs,chips). Shortley after lunch they annouce it's time to feed the stingrays.
You leave the island at 2pm. The beach is nice and clean, my boys age 6 and 9yrs made sand castles while my DH and I basked in the sun. This was a great adventure. We will definitly snorkel with the stingrays again.
Have a great trip.