Southwest of Hanapepe on Kauai, the snorkeling at Salt Pond Beach Park is well known for its variety of common reef fish. Salt Pond Beach Park has an outer reef and lava wall that protects the small cove. Salt Pond is a great place for kids and beginning snorkelers. You may encounter wrasse, parrotfish, tangs and humuhumunukunukuapua’a (Hawaiian state fish aka rectangular triggerfish). From May through September, the surf off Salt Pond Beach is affected by seasonal southerly swells that kickup the large waves and generate strong currents so make sure to exercise caution and stay inside the protective cove.
To reach the snorkeling in Kauai by air, fly into the Lihue airport (LIH). There are direct flights from Los Angeles, San Francisco, Seattle, Denver and Honolulu. While most visitors to the island rent a car, it is possible to use the public bus but keep in mind that its small and slow. Plus, most of the main snorkeling beaches are well off the bus route requiring some hiking. If you do rent a car, make sure to leave the inside empty when at the beach to avoid attracting break-ins.
To reach the Salt Pond snorkeling from Lihue, head south on SR530. Continue west on Kaumualii Highway (SR50) to Hanapepe. Just past Hanapepe, turn left heading south on Lele Road. Turn right on Salt Pond Road (Lokokai Road) to Salt Pond Park. There is plenty of parking.
Before snorkeling at Salt Pond Beach Park, make sure to check the current surf report. The waters off Kauai are known for potentially strong currents, high surf and rogue waves. Luckily, there are excellent up-to-date surf reports that can provide guidance on these adverse conditions. WIth the usually rolling surf, it is strongly discouraged to use open-tube snorkels which are common at snorkel rental locations -- only use snorkels with a dry-top splash-guard and a sump purge-valve in the mouth piece.
Overall, Salt Pond Beach Park is the 13th most popular snorkel dive spot of all 23 snorkeling dives in Kauai.