We took a taxi to Porto Mari for $40 each way and very much enjoyed the snorkeling and facilities there. There were lots of fish and many varieties to admire, including a couple that I had never seen before. One looked like a kind of squid but with only two tentacles and a thin, fluttering skirt all around it that kept it in the same position. It also kept changing color - very fascinating! The left side of the cove is filled with broken coral pieces, millions of them, with newer, live coral growing in spots and attached to a variety of objects. While the broken stuff is mostly short tubes of different sizes the new coral seems to be mostly brain coral. If you swim straight out from the beach there is a rope that marks the drop off. Even just snorkeling this is a dramatic view, as the bottom just drops and your view enlarges exponentially - a really cool sight.