The other dive option is the Cooper River. When diving in Charleston area, I have sometimes booked an ocean trip on Saturday and a Cooper River trip on Sunday, since I have only had about a 50% go rate for ocean dives in the Southeast (based on a small number of outings though) due to sea conditions. As the Cooper is a river, there are things you do not need to worry about that you would on an ocean trip. But...and its a big but...the Cooper River fossil dives are in black water where you literally lose all light once you are down 10 ft or so and even with a serious light, will not be able to see your outstretched hand at depth. They are certainly not for everyone. The dives will consist of what feels like parachuting to the bottom (which you cannot see and so you just descend until you hit it), and then getting horizontal, facing into the current most of the time, putting the light up to your head and your face about 8 inches from the bottom so you can look for sharks teeth...all the while with the mostly irrational concern that you might come across an alligator. Some really take to it, others abhor it.