Haena Beach State Park
In the North of the island across from the dry cave and 9 miles past Princeton you will come to a great location for snorkeling. Once you arrive here you simply need to walk down the sandy beach to the right for awhile until you reach Tunnels. Here the water is flat and the reef is a considerable ways out, but it is great snorkeling and absolutely worthwhile. The best time for snorkeling here is in the summer.