My DH and I did the Catamaran and Reef Snorkel last October on the 4-night Wonder cruise.
We loved it! We met up at 9am in the Promenade Lounge - per our instructions that were left in our stateroom. It didn't take long to get clearance and have everyone checked in. You get these cute stickers for easy identification...I think it's more for the Disney experience rather than any actual security or ID use.
We walked a short distance from the ship, past the carriage ride stands, lots of hair braiders, and to the dock right in front of the straw market. We boarded the catamaran there. The captain used the engines to get us to the reef, the ride was great. Lots to see, talked to other people on board, listened to the captain and other crew members tell us things about the island, the water, and the equipment. They handed out fins, snorkels, masks, and life jackets as we approached the reef. (side note - I recommend trying to get one of the vests that doesn't hook up from between your legs...I had one, and when I wasn't in the water, it was not very comfortable.
LOL) They were pretty thorough on instructions, as both DH and I had never snorkled and we felt very confident once instructed that we could handle it. They drop anchor a couple hundred yards from shore where the reef is, then one by one we disembarked from the catamaran right into the water. The life vests definitly helped, because you couldn't touch bottom, and there were several times I had to stop and clear my mask or snorkel. Both would have been extremely difficult without the aid of the vest. They gave us an hour to explore within a certain area...the area was basically within a certain distance from the catamaran...so they could keep an eye on you in case of need. There were several children on the excursion and none seemed to have any problems. The water is pretty deep, but it was hard for me to judge distance. Sometimes I thought I could just reach out and touch a fish, only to find it had to be several feet away...go figure
There were plenty of fish to see too...I was very pleased because I had heard that other people had gone on other snorkeling excursion and didn't get to see anything.
They blew a horn to let us know when time was up, then we all slowly made our way back to the ship. Getting out can be tricky. After being in the water for an hour, my body got use to the bouyancy...then getting up on the ladder and pulling myself out of the water reminded me that gravity does exist.
Once back on board, we turned in our equipment, got hosed off with fresh water, got refreshements and found a spot to lay back and relax. The captain used the sails on the way back, which took a bit longer, but was wonderful. Most of the kids sat or played in the netting between the thingys(don't know technical term)...mostly because they could watch the water fly past under the boat and occasionally got sprayed. I on the other hand, laid back, enjoyed the scenery and relaxed. We reached the dock all to soon for my taste.
DH and I went straight back to the ship after the excursion and showered...then hit lunch around 1pm.
One piece of advice...lots of sunscreen on your back, neck, ears, and don't bend your head down to see something closer. LOL My DH burns easily...I'm not as bad...a really good tanner...I was able to put one coat of spf30 on and I was fine...he on the other hand was quite red afterward. My major malfunction was forgetting that I'm breathing out of a small tube with a hole on the top and that it worked both ways. So I would get caught up in looking at something, dip my head to low...and mmmm....yummmm...lots of sea water would come flooding into my mouth and throat. Cough, cough...cough...breath...okay...start again.
Go, have fun!