Sometimes the best things down here around the islands is what you luck into. Places like this are perfect to enjoy all types of watersports in the Atlantic Ocean. The water clarity makes it so nice for all ages. Up on the land are all that you will need for picnicking and there is a playground area for younger children. This park is mainly used by locals, and typically has tons of room.
You can take the boat from here and go to some really good dive sites. The options for fishing and scuba are just unlimited and we like to do both and usually alternate the activities each day, weather plays a factor for sure. Here our the picks for scuba diving: City of Washington (Shipwreck just offshore of Elbow Reef known for an abundance of friendly fish populations) - Pickles Reef (Loaded with marine life and in only 10-25 feet) - Christ of the Abyss (The four thousand pound bronze sculpture lies in 20+ feet of water)
You can rent a boat for cheap or use their boat ramp at Sea Bird Marina (seabirdmarina.com). This is in Layton on Long Key and the water is great there and has some other islands to explore. It is on the way down a bit, half way to Marathon. We like the area a lot. Again, it is Sea Bird Marina in Layton Florida Keys.
Fish are everywhere, but you have to have a valid Florida license to reel one in. You can call and get a fishing license via the Key Largo Tax Collector. Once you have it, the boat ramp puts you right in the action.