We did this in June 2002 and we had a wonderful time. It was very peaceful. There is a shallow cove if you have little ones. A nice snorkeling area, but you have to walk over some rocks to get out to the deeper water. I recommend water shoes for this instead of fins. They also have rental crafts, they were non-motorized at the time.
There are two trips back to the ship at 2 and at 4. It is about a 45 min ride.
We also did the Catamaran sail and reef snorkel in June 2003. It was very nice. We were back on the ship around 1ish which I liked because we got lunch on board, cleaned up, went into the straw market (twice because we ran out of cash!) and all before my 5:00 spa appt.
Lorie