Wayne Y.
Yelp
I promised a seasoned snorkeler here that I would help keep this place a secret. Conflicting duties, so here is the Yelp review. :-)
After frustratingly trying to find a nice tranquil snorkeling spot near Captain Cook, we decided to drive NORTH of Kona to get at this place, which was listed in the Moon Guide as a potentially good place. We were so glad we did. When we pulled up, there was only one car in the dirt parking lot. It was a sheltered tidal flat with many pools and shallow ocean. Immediately, there were a bunch of sea turtles. As we traversed along, we saw many schools of fish in the shallow waters as well as some beautiful coral.
Now, I've been snorkeling in other parts of the world. This one was pretty good and very easily accessible. There are many eels and sea snakes too. Remember to wear your water moccasins as there are a ton of sea urchins here.
Note: this is not a swimming beach. Come here with your own snorkeling gear and you can spend an hour or two wandering on your own and enjoying tranquility and the abundant marine life. Make sure you get out to the open ocean segment, as that's where a lot of the fish are.