I can only tell you about Grand Cayman and Cozumel
The ships dock in the port of Georgetown,GC
. It is a long walk to the beaches, take a taxi.
In Cozumel there are plenty of beaches a short walk from the pier. If you want to go to the underwater park, Chankanaab Park, you will need a taxi or get some friends together and share a rental. Also you can bike around the island. it is not very big.
here is the web site for the park. www.cozumelparks.org.mx
Hope that is some help.
In Grand Cayman there is actually decent "walk in" snorkelling all of 1 block from the tender pier. As you walk off the tender walk to the right along the water about 1 block.
You will come to a dive shop. At the water's edge there is a staircase leading into the water. The snorkelling out about 75 to 100 feet from the staircase is actually pretty decent . You will not be alone snorkelling right there. You can rent or buy stuff from the dive shop and if memory serves they also serve cold drinks and stuff right there.
I think the best walk in snorkelling in Cozumel is probably Chankanaab Park (spelling?).
Cayman - go to the right for about a 5 minute walk and you will see Eden Rock dive shop with a pier over the water. All piers are public and free and the snorkeling is great there as well as the diving. You can see the dive flags from the tender when you come in and check them out on the web. You can rent gear and lockers there too. We have scuba dived there.
Cozumel - Best snorkeling from beach is Chankanaab Park. $10 cab ride and $12 a person to get in and snorkeling free or you can rent gear and lockers from dive huts on the beach. They also have vacation scuba at the dive huts and it is a great dive!! Check it out on the net.
Shark Ray Alley in Belize is a GREAT excursion - a little pricey but worth it. You take a speed boat for about 1 hour to the spot in the middle of nowhere and snorkel from the boat. They then take you to San Pedro on a Cay off Belize and there is a beach and town and lunch at a local restaurant was great!! Some tours go to Cay Caulkner instead - read the discription. I prefer San Pedro as in the Madona song "Isla Bonita".. Debbie
agree with the others for walk-in snorkeling on Grand Caymen its just a short walk from the tender pier to Eden's Rock or Devil's Grotto - no beach here. If you want beach on Grand Caymen you should grab a cab to 7-mile beach - not sure if there is snorkeling there or not.
Cozumel - about the best from shore snorkeling is to be found at Channunkaab National Park.