Hello. Well, I have been to Stone Beach. It is beautiful, and stretches down the coast. My mom goes to Mazatlan every year with her friends, for a 2 week timeshare. I go sometimes. They say Stone Beach is there favorite. I think Deer Island, might have been the island that I saw when I parasailed down there, at the beach where all the hotels are. If that is it, I saw a few people on it. I am not familiar with Stone Island, do you by chance mean Stone Beach? I know there are a few islands off the Mazatlan coast. I am going there Dec 3, for 4 nights. Maybe I can check on some info for you, if you need me too. Let me know, it is no problem. Lil' Lori