Koh Hong (Krabi)

Koh Hong sits inside Than Bok Khorani National Park, a short boat ride from Ao Nang, and its draw is a lagoon you can only reach by kayak: paddle through a narrow gap in the limestone cliffs and the passage opens into Thale Nai, a nearly enclosed pool of flat, jade-green water ringed by sheer rock walls.

The lagoon is the main event. Longtail and speedboat tours anchor offshore, then hand passengers into kayaks for the short paddle through the cave mouth — there’s no walking route in. Inside, the water is still enough to see straight down, and the cliffs block enough wind that it feels sealed off from the open sea outside. Snorkeling around the outer reef is decent rather than exceptional, with parrotfish and the odd reef shark sighting reported, but most visitors come for the lagoon and the beach, not the coral.

Since 2020, a second draw has pulled some of the crowd uphill: a walkway of 419 metal steps climbing through shaded forest to a viewpoint with a 360-degree outlook over the lagoon and the surrounding karst islands. It takes about 20 minutes each way and isn’t part of every tour itinerary, so ask before booking if you specifically want it included.

Insider Tip: Tour quotes rarely include the national park fee — it’s paid in cash at the gate or to your guide on arrival. Budget an extra few hundred baht per person on top of whatever price you booked.

Watch out: Don’t confuse this with Koh Hong in Phang Nga Bay, off Koh Yao Noi — a different island with its own enclosed lagoon, often marketed with near-identical language. If a tour description doesn’t specify Krabi or Ao Nang as the departure point, ask before you pay.

December through April brings the calmest seas for kayaking; outside that window, swell can make the cave entrance to the lagoon rougher to negotiate. There’s no accommodation on Koh Hong, so this is strictly a day trip, typically bundled with stops at Koh Poda or Koh Lao Lading depending on the operator. Bring cash for the park fee, a dry bag, and reef-safe sunscreen.

Combine a visit with Koh Poda or Noppharat Thara Beach, both common stops on the same Ao Nang day-tour circuit.