Hi: Just back from a week on Marco Island. Sorry to say I was very disappointed. It's a very overpriced area, in my opinion.
Water clarity is zero. Water temperature is very cold.
We drove to the Keys one day hoping to find better beaches and water. John Pennecamp State Park was highly rated. BUT! --- in order to see anything in the water, you must rent a boat to go out 3-4 miles from shore.
If you are looking for a beach type vacation, I would definitely go elsewhere.
We took our 2 teenagers and were looking very hard to find anyone under 50 on the island.
We did drive up to Fort Myers and found lots more younger people in that area.
Driving is a disaster around the area. I-75 was backed up everyday we were there. I have never heard as many sirens as I did on this vacation.
Sorry to sound so negative, but there are so many wonderful places to vacation, I wouldn't encourage anyone that enjoys the ocean, snorkeling, watersports to go to Marco.
Please email me if you would like more specific information.