Generally speaking, the calmest water and best snorkeling can be found on Kauai's North Shore in summer and South Shore in winter. The East Side, known as the windward side, has year-round, prevalent northeast trade winds that make snorkeling unpredictable, although there are some good pockets. The best snorkeling on the West Side is accessible only by boat.
A word on feeding fish: don't. As Captain Ted with HoloHolo Charters says, fish have survived and populated reefs for much longer than we have been donning goggles and staring at them. They will continue to do so without our intervention. Besides, fish food messes up the reef and -- one thing always leads to another -- can eliminate a once-pristine reef environment. As for gear, if you're snorkeling with one of Napali boat tour outfitters, they'll provide it. However, depending on the company, it might not be the latest or greatest. If you have your own, bring it. On the other hand, if you're going out with SeaFun or Z-Tourz, not to worry. Their gear is top-notch. If you need to rent, hit one of the "snorkel-and-surf" shops such as Snorkel Bob's in Koloa and Kapaa, Play Dirty in Kapaa, Nukumoi in Poipu and Waimea, or Seasport in Poipu and Kapa, or shop Wal-Mart or Kmart if you want to drag it home. Typically, though, rental gear will be better quality than that found at Wal-Mart or Kmart. If you wear glasses, you can rent prescription masks at the rental shops -- just don't expect them to match your prescription exactly.
Just because we say these are good places to snorkel doesn't mean that the exact moment you arrive, the fish will flock -- they are wild, after all. The beaches here are listed in clockwise fashion starting on the North Shore.
Although it can get quite crowded, Kee Beach (At the end of Rte. 560) is quite often a good snorkeling destination. Just be sure to come during the off-hours, say early in the morning or later in the afternoon. Snorkeling here in winter can be hazardous -- summer is the best and safest time for snorkeling -- although you should never swim beyond the reef.
The search for Tunnels (Makua) (At Haena Beach Park, near end of Rte. 560, across from lava-tube sea caves, after stream crossing) is as tricky as the snorkeling. Park at Haena Beach Park and walk east -- away from Na Pali Coast -- until you see a sand channel entrance in the water, almost at the point. Once you get here, the reward is fantastic. The name of this beach comes from the many underwater lava tubes, which always attract marine life. The shore is mostly beach rock interrupted by three sand channels. You'll want to enter and exit at one of these channels (or risk stepping on a sea urchin or scraping your stomach on the reef). Follow the sand channel to a drop-off; the snorkeling along here is always full of nice surprises. Expect a current running east to west. Snorkeling here in winter can be hazardous; summer is the best and safest time for snorkeling.
Lydgate Beach Park (Just south of Wailua River, turn makai off Rte. 56 onto Lehu Dr. and left onto Nalu Rd.) is the absolute safest place to snorkel on Kauai. With its lava-rock wall creating a protected swimming pool, this is the perfect spot for beginners, young and old. The fish are so tame here it's almost like swimming in a saltwater aquarium.
You'll generally find good year-round snorkeling at Poipu Beach Park (From Poipu Rd., turn right on Hoone Rd.), except during summer's south swells (which are not nearly as frequent as winter's north swells). The best snorkeling fronts the Marriott Waiohai Beach Club. Stay inside the crescent shape created by the sandbar and rocky point. The current runs east to west.
Don't pack the beach umbrella, beach mats, or cooler for snorkeling at Beach House (Lawai Beach) (Makai side of Lawai Rd.; park on road in front of Lawai Beach Resort). Just bring your snorkeling gear. The beach -- named after its neighbor the Beach House restaurant (yum) -- is on the road to Spouting Horn. It's a small slip of sand during low tide and a rocky shoreline during high tide. However, it's right by the road's edge, and its rocky coastline and somewhat rocky bottom make it great for snorkeling. Enter and exit in the sand channel (not over the rocky reef) that lines up with the Lawai Beach Resort's center atrium. Stay within the rocky points anchoring each end of the beach. The current runs east to west.
Nualolo Kai was once an ancient Hawaiian fishpond and is now home to the best snorkeling along Napali Coast (and perhaps on all of Kauai). The only way to access it is by boat, and only a few Napali snorkeling tour operators are permitted to do so. We recommend Napali Explorer and Kauai Sea Tours.
With little river runoff and hardly any boat traffic, the waters off the island of Niihau are some of the clearest in all Hawaii, and that's good for snorkeling. Like Nualolo Kai, the only way to snorkel here is to sign on with one of the two tour boats venturing across a sometimes rough open ocean channel: Blue Dolphin Charters and HoloHolo. Sammy the monk seal likes to hang out behind Lehua Rock off the north end of Niihau and swim with the snorkelers.
SeaFun Kauai. This guided snorkeling tour, for beginners and intermediates alike, is led by a marine expert, so not only is there excellent "how-to" instruction, but the guide actually gets in the water with you and identifies marine life. You're guaranteed to spot tons of critters you'd never see on your own. This is a land-based operation and the only one of its kind on Kauai. (Don't think those snorkeling cruises are guided snorkeling tours -- they rarely are. A member of the boat's crew serves as lifeguard, not a marine life guide.) A half-day tour includes all your snorkeling gear -- and a wet suit to keep you warm -- and stops at two snorkeling locations, chosen based on ocean conditions. The cost is $80. Check in at Kilohana Plantation in Puhi, next to Kauai Community College. 808/245-6400 or 800/452-1113. www.alohakauaitours.com