Have done both as a dive, and snorkeling. Great for both. Snorkeling we kept close to shore where the wall has great fish life and decent living sponges and coral. Lots of coral rubble inshore, which is storm broken, but great hiding for many different fish. Water over 5 meters is full of good coral and great for surface diving. As a dive it is hard to beat. The first portion is a true wall; vibrant an alive from 10 to 30+ meters. It is pretty easy to tell when you are approaching Karpata as the slope changes, and some long sloping ridges go well out from shore. Only divers who have navigated their way before, and are not intimidated by the 'no return' aspect of the entry should do this. Snorkelers should be decent swimmers who are comfortable with a good sized choppy swell. Be advised that the current at the surface may not be the same as the current below 15 meters.