Beach day & snorkeling recommendations?

[serotta4]

My family is headed on a Royal Caribbean cruise this summer and will be stopping in Costa Maya. There are 2 adults and 2 teenagers. Our desire is to find a place to relax on the beach, swim in the water, and snorkel off the beach (if possible). We will also be stopping in Cozumel and Roatan and looking to do something similar in those destinations. Does anyone have any recommendations regarding any of these three stops for this type of activity? 

• Should we book through the cruise line or on our own? (I understand some of the pros and cons as far as pricing, but my question is more around is it easy and safe to do things on our own?)

• What is the best beach for relaxing and shore snorkeling? How far is the beach from the port?

• Is it safe to arrange our own transportation? If so, are there specific companies to use/not use?

• Are there any other considerations that we don't want to miss in Costa Maya?

THANK YOU!