Snorkeling in Nassau is pretty cool. You'll see mostly fish, maybe a barracuda or two and perhaps stingrays. The only places I have seen sea turtles were Honeymoon Bay at St. John and in Barbados. If you ever make it to North Carolina, head for Baldhead Island. There is a Sea Turtle Sanctuary there.
I am assuming you are going to take an excursion on a snorkel boat. If you don't have your own fins and mask they will be provided for you by the tour operator. They will also give you instruction on how to do it before you jump in.
What to bring…
A water wallet. This is a small, waterproof plastic container with a lanyard so you can wear it around your neck while in the water. In it you will put your ship card, cash or traveler’s checks, driver’s license, credit card etc. These can be purchased in a sporting goods store or the ship’s gift shop. I have found the ones purchased on the ship are of better quality and less likely to leak.
Cash or travelers checks if you haven’t pre paid. (No credit card machines on snorkel boats) Also a credit card if you plan on doing some shopping while ashore. Also a drivers license because some stores require ID if using a credit card or travelers checks.
My bathing suit doubles as shorts and I usually wear a t-shirt and sometimes a Hawaiian shirt over that. You can also purchase men's "water shorts" from Land's End. I have some of those too. Susan wears shorts and a shirt over her bathing suit.
Susan has a shopping bag that we pack other stuff in. Needless to say, sun block is a must. As you disembark the ship the crew will be there to sell you bottled water which is way over priced. Wait until you’re off the ship and buy your water locally. You are allowed to take beach towels from the ship so no need to pack your own for the cruise. Don’t lose them though or you’ll be billed about $25. Bring a waterproof camera or two. You can get them at places like K-Mart, Target, etc. Buy Kodak or Fuji. I have found out the hard way that the “off brand†ones are more likely to leak.
I may get scolded for this last one because you’re not supposed to take food off the ship for agricultural reasons. Before we leave for a cruise we always pack a small box of zip lock sandwich bags. On shore day mornings we will order an extra fruit plate from room service and pack the fruit in the bags. Not fresh fruit but diced melon, pineapple, etc. Very refreshing after being in the salt water. Some tour operators provide refreshments and some don't. Since the fruit plates are already prepared for eating I assume that they contain no insects or pesticides that could harm the eco system of the island.
Snorkeling is great, my favorite thing except maybe for rum punch. My snorkel bag is part of my living room décor. It sits close to the front door patiently awaiting the next time I sling it over my shoulder and head for the airport.
Enjoy! :beach: