We've snorkeled maybe 5 or 6 times on various reefs around Cozumel. Mostly from catamarans or small boats. The very best snorkeling we have done is by far Chankanaab Park. No contest. You can also do a "test dive" for less money than from your ship or in many places right from the beach in the park. They give you a short course and then take you out to maybe 30 ft. or so and you see arches and natural coral, many fish, etc. My husband did it and couldn't stop talking about it. He then got PADI certified in Cancun the following year. So if you are thinking of trying diving, it's also a VERY good spot and you can walk right in from shore.