There are a handful of diving outfits that you can choose from on Koh Rong Samloem.
EcoSea has bungalows on the island, at EcoSea Dive and Bungalows, and is serviced by the fast boat Speed Ferry. They offer fun dives as well as SSI- and PADI-certified courses. PADI Open Water costs from $320 for a three-day course. Their instructors come from Canada, the UK and Japan and are said to be good. EcoSea has also created an artificial reef by sinking a boat just off the shore near M'Pay Bei Village.
Scuba Nation do dives on Koh Rong Samloem but don't offer accommodation there. However, it's possible to stay on the island and still organise dives through them. They offer PADI and National Geographic Diver courses.
The Dive Shop runs daily boats to Koh Rong Samloem with a jetty and dive centre based on Sunset Beach; their Happa Bungalows are on the same stretch of sand. Fun dives are $95 for two. They also offer PADI scuba diver certification for $320, open water for $380 and a range of specialist courses such as PADI Digital Underwater Photographer.
Snorkellers can usually check out gear from their own hotel or guesthouse. Some do it for free, for guests, while others charge around $2. Some of the best places to snorkel are the rocks at either side of Lazy Beach, M'Pai Bei's Long Beach and around Koh Kon.
The Beach organises trips to Koh Kon and the dive centres are all able to arrange snorkelling tours.
Eco Sea: Serendipity Beach Rd, Sihanoukville; T: (012) 654 104; www.ecoseadive.com.
Scuba Nation: Serendipity Beach Rd, Sihanoukville; T: (012) 604 680; www.divecambodia.com.
The Dive Shop: Serendipity Beach Road, Sihanoukville, T: (034) 933 664; www.diveshopcambodia.com.
By Nicky Sullivan.
Last updated on 25th September, 2016.