Hey there. I have spent a lot of time in this cruising ground and would be happy to give you some tips. First of all, try to get away from Lauderdale at such a time that you can make it to the lighthouse at the south end of key biscayne before sunset. There is an awesome little hidey hole with a restaurant there in Bill Baggs state park. It is a great place to hang in the morning and then you can you can spend a day snorkeling in the various cuts just to the south near stiltsville and work your way into a nice anchorage in the lee of Elliot or Sand Key. The next day, if you line up the entrance (seaside marker) to Angelfish Creek and the tower on Ajax reef and run towards Ajax, you will run up on some awesome big coral
formations that are like 4' at the top and 15' at the bottom. These are some of your best diving
opportunities of the whole trip. That night you can anchor
near Rodriguez key. Cruise
on down Hawk channel and cross to the bay side at the seven mile bridge near marathon. BE SURE TO LISTEN TO THE WEATHER
AND CHECK FOR FRONTS! Dont get caught on the Florida
Bay side when a front comes through. If you wind
up on the bay side, there is a great anchorage near big pine key in the creek between no name key and big pine key (porpoise creek.) check the holding tho if there is a blow...the bottom is smooth rock. from there if you leave spanish harbor and head
Bay there is just wilderness on your left until you get to the Key West
channel. Just be sure you are snug and well protected if a front comes through. It will blow like stink from the northwest then shift slowly eastward until it clocks back to the southeast before the process repeats when the next front arrives.
There are some nice ledges to dive on the way from big pine to key west. not much around key west for snorkeling until you get down to sand key hopefully on your way to tortuga! good luck and have fun!