The best snorkeling is to the right side of the point where you can snorkel with Hawaiian reef fish at one of the rare Hawaii tombolos. (parrishkauai.com)
Both of these tour are conducted in Marino Ballena National Park, Terraba Mangroves, Ballena rock, Whale's tail tombolo and Dominical. (retreatvacations.net)
[1] Two or more tombolos may form an enclosure (called a lagoon) that can eventually fill with sediment. (en.wikipedia.org)