I cant swim a lick...and at my age I am too old to try to learn. But I love to snorkel. I wear a life vest and have a blast...I even took a catamaran 7 miles off of key west and went snorkeling and felt very safe with my life vest one...I snorkel at chanacanob in cozomel too..you will love it.
The salt water is very bouyant, and with the snorkel vests you don't need to know how to swim. If you can move your arms and kick your legs..you got it. Thats all you need to move around, you won't sink
getfuzzy, not to worry. As others have stated, the life vest will hold you up very well. Most excursions are to islands where you can wade into the water, at your leisure. Make sure you book a tour where the excursion is land based. Someone mentioned Chankanaab National Park in Cozumel. That's a great example. Two others are Coco Cay near the Bahamas and Goff's Cay in Belize. Have fun. Snorkeling is wonderful and relaxing.
A'ndrea