The Rock Islands of Palau are one of the most extraordinary landscapes in the Pacific. Roughly 250 to 300 limestone islands rise from the turquoise lagoon between Koror and Peleliu, their bases undercut by centuries of erosion so they look like green mushrooms floating on the water. The whole area was designated a UNESCO World Heritage Site in 2012, and for good reason -- there is nothing else quite like it on earth.
For most visitors, the Rock Islands mean kayaking, snorkeling, and diving. The marine lakes are the star attraction, particularly Jellyfish Lake, where you can swim among millions of golden jellyfish that have lost their sting after evolving in isolation for thousands of years. The diving around the outer edges of the islands is world-class, with sheer walls, strong currents, and an abundance of sharks, rays, and pelagic fish. Blue Corner and German Channel are legendary dive sites.
Beyond the water, the islands themselves are worth exploring. Some have hidden beaches accessible only by boat, others have caves with ancient Palauan rock art. The vegetation is thick and the birdlife impressive. Most visitors explore the Rock Islands on day trips from Koror, which is the main base for tour operators and dive shops. You will need a Rock Islands permit, available from the Koror state government, which covers entry to Jellyfish Lake and the Southern Lagoon.