Koh Rong Sanloem (Khmer: កោះរុងសន្លឹម, also Kaoh Rong Sanloem) is an island off the coast of Sihanoukville, Cambodia, 4 kilometers south of Koh Rong island. It is around 9 kilometers long (north to south), 4 kilometers wide (east to west) and 1 kilometer wide at its narrowest point. Its distance from the local port of Sihanoukville is 25 kilometers (beeline) and 23 kilometers (beeline) from the Serendipity/Ochheuteal beach pier. The word "Sanloem" translates to: 1. drowsiness and to: 2. far out and hard to discern, in a wider sense. Inconsistencies on how to spell the island's name in its Latinized version date back to the 19th century. The first controversial spelling variants were issued by map makers during French rule. Alternatives have since become widespread and are in common usage. Often confusion ensues as Google Maps offers the phonetically most consistent variant, whereas Google Search redirects to an alternative.
Koh Rong Sanloem lies within Sihanoukville province's Mittakpheap district in Commune 5 (Sangkat Koh Rong). Alongside its sister-island Koh Rong it has developed into a popular holiday destination for individual travelers. With respect to the island's very tiny population, the tourism sector is by 2014 the core economy.
More than a dozen guest houses and bungalow resorts have been established by 2014. Although most of these businesses are scattered all over the whole island, Saracen beach has become the primary place of arrival and departure with the highest number and density of resorts followed by Ma-pay Bay located at the northern end of the island. Accommodation and prices range from cheap dorm beds to well furnished solid bungalows. There are a few daily scheduled ferries (around 2-2.5 hours) and 2 speed ferries (25 min and 45 min) to the island. Departure is at the local port of Sihanoukville and the piers at Serendipity beach and Victory beach.
The island's formidable jungle is the ideal habitat for a great variety of endemic Invertebrate species. Vertebrates are less abundant and, typically for island populations, are small in comparison. Amphibians and reptiles are the most numerous and the island's brooks, ponds and streams are home to a variety of small freshwater fish. Birds include the Great hornbill, the King Fisher and the Osprey. There is a group of Macaques living on the island and rodents are very common as a consequence of human activities. Small reefs and the rocky surface of the surrounding waters are home to a remarkable variety of marine species. Divers and Snorkelers regularly emphasize the presence of delicate miniature Eco-systems, seahorses and nudibranches are particularly diverse.