Haʻena
The best snorkeling beach on Kauai's north shore — a broad sandy bay with a fringing reef system that creates the "tunnels" of the name: coral archways, swim-throughs, and lava formations with exceptional fish diversity. Water clarity is outstanding when the sea is calm. The backdrop of fluted Na Pali ridges directly behind the beach makes this one of the most visually dramatic settings for a beach day in Hawaii. The Ha'ena permit system means the beach is never overcrowded. Combine with the Limahuli Garden (10 min further) or as the beach portion of a Na Pali hike day.
No beach entry fee. Park at Ha'ena Beach Park (requires Ha'ena State Park day-use permit at gohaena.com, $5/person + $10 parking — book 30 days ahead). Gear rental from Snorkel Bob's in Princeville or Kapaa. Best summer snorkeling is on the right (east) side of the bay.
SUMMER ONLY for snorkeling (May–September). In winter, north shore swells make the entire bay unsafe for swimming. Summer mornings are glassy and visibility is best before afternoon trade winds build.