Koh Rang Ka Chio

Ko Rang Ka Chio is one of roughly 40 islands inside Mu Ko Chumphon National Park, a marine park established in 1999 covering Chumphon’s coastal waters. Its main claim to fame predates the park by a century: King Chulalongkorn (Rama V) sailed out here three times to watch swiftlet nests being harvested from a sea cave on the island’s south side, and had his royal monogram carved into the rock at the cave entrance, where it’s still visible today.

The island itself is small, with around 100 metres of white sand beach and clear, emerald-toned water good for swimming. Swiftlets still nest in the same cave the king came to observe, their calls carrying across the water alongside the sound of waves against the rocky shoreline elsewhere on the island. Coral fringes the surrounding reef, best explored by snorkelling or diving between March and October when the sea is calm enough for good visibility — outside those months, swells make both the crossing from Chumphon and the underwater conditions rougher.

Because it’s a national park island rather than a private beach, there’s no resort or facilities beyond what the park itself provides — no shops, no restaurant, nothing beyond the beach and the cave. Boats from Chumphon town run as day trips, typically bundling Ko Rang Ka Chio with a couple of the park’s other islands rather than visiting it alone.

Insider Tip: Ask your boat operator specifically about the royal inscription and swiftlet cave — some day-trip itineraries skip the cave landing if the group is focused only on snorkelling, and it’s easy to miss otherwise.

Watch out: The swiftlet nests are a licensed harvest site, not just scenery — keep noise down near the cave mouth and don’t attempt to climb toward the nests, which sit high on the cave walls and are actively collected.

Combine the trip with Mu Ko Chumphon National Park itself or nearby islands like Ko Thalu and Ko Mattra — most Chumphon boat operators run multi-island day trips rather than a single-island charter. Bring reef-safe sunscreen, water, and snacks, since nothing is sold on the island itself.