It is more difficult to run on the sand let alone walk on it so by moving and workout to the sand your challenging yourself. I did not wear shoes when I did this but if you have weak ankles or any history with ankle injuries it is probably best to wear sneakers or even a brace if you have one. (Or if you want something a little easier you can move down the beach to the hard sand.)
So with out further adieu here is my beach workout. Enjoy!