I lived in the Keys for a few months and while the keys have a poor reputation for shore diving those of us who live there have the need to get wet and can't always afford the money or time to get on a boat. You don't expect to see much on shore dives there and the vis is usually poor so I wouldn't travel just to shore dive the Keys but it's very doable. Bahia is a nice spot and it's usually easy diving, watch the tides of course or you can find yourself a long ways from where you started.