There is an abundance of marine life and decent coral reefs around Sihanoukville and its islands. While there are a few dive shops around, the numbers diving here are relatively small meaning you will nearly always have the dive spot to just your group. It's also cheap to dive here which is another bonus. January to April is usually the best period, with the waters at their calmest meaning good visibility. July to September are the stormiest months, so sometimes not the best conditions to be out in. If the conditions are right, the diving here is certainly worth checking out if you love diving or want to learn. Visibility ranges from 5-25m but is usually around 10m for the islands nearby. The best visibility in the area is undoubtedly around Koh Prins and Koh Tang which are 4-5 hours from the mainland, often with 30m visibility. This requires an overnight on a liveaboard from Sihanoukville, or you can stay on Koh Prins. Around $320 each will get you a two night liveaboard with 8 dives, food and drink. From the mainland, it takes a couple of hours each way on the boat to get to Koh Rong Samloem, which has a good portion of the dive sites nearby. An excellent option is to stay on Koh Rong Samloem as most dive shops pick up people/gear from here and EcoSea Dive also has a resort with accommodation in Mpay Bay. It's around $80 for 2 fun dives, $380 for a PADI Open Water course. Here are the 2 of the most reputable outfits in Sihanoukville: Suba Nation Email: email@example.com Tel: +855 12604680 Address: Serendipity Beach Road, Opposite Holiday Villa Nataya. Website: www.divecambodia.com Dive Shop Email: firstname.lastname@example.org Tel: +855 34933664 Address: Serendipity Beach Road Website: www.diveshopcambodia.com These 2 also receive good reviews based on Koh Rong Samloem: Cambodian Diving Group Tel: +855 886856986 Address: Based in Mai Pai Bai village Website: www.cambodiandivinggroup.com Coral Gardens Dive Resort Email: email@example.com Tel: +855 966833197 Address: Based in Saracen Bay Website: http://coraldivers.org Take a look at our summary of the main dive sites in the area for what you are likely to see: Koh Rong Samloem (9 dive sites) All the dive sites here are relatively shallow and you can see most stuff around the 12m mark, 18m is the deepest you need to go. Between the dive sites you can expect to see large cobia (kingfish up to 2m long) that resemble grey reef sharks, coral with large barrel sponges and large bommies, nudibranch, parrotfish, pipefish, scorpionfish, puffer fish, juvenile fish, cuttlefish, pufferfish, crustaceans, moray eels, small octopus, rays and blue-spotted rays. Koh Rong (7 dive sites) You're likely to see schools of huge Barracuda, Yellow Box Fish, enormous Sweet lips, lots of groupers, cuttlefish, bamboo sharks, loads of Nudi, big Mora Eels, schools of Cobia and even dolphins! Khmer Garden has the added bonus of being just off 7km beach, which is a wonderful sight from the boat. Koh Koun (Koh Kon) (4 dive sites) The north and west are deeper dive sites at around 16m with more corals and rocky outcrops. The south and east between 6m-14m are shallow corals with sandy areas. You can expect to see sea bass, barracuda, large parrot fish, schooling trevally, unusual nudibranch, anemones, box fish, large parrot fish, schools of yellow goatfish, sea bass, large snappers and sweetlips, octopus, squid and sea-horses. There are some good spots for a night dive with electric blue-spotted stingrays mingling with moray eels, bamboo and cat sharks. Koh Tas (3 dive sites) Has three relatively shallow dive sites at around 8-9m and a good site for beginners. You can expect to see beautiful shallow coral reefs and bommies, an abundance of juvenile fish, scorpionfish, moray eels, boxfish, large parrot fish, schools of yellow goatfish, sea bass, large snappers and sweetlips. Koh Tang (9 dive sites) Situated around 4-5 hours off the mainland about 2.5 hours south-west of Koh Rong Saloem. Its distance from the mainland means you are unlikely to see other divers here, and it has some of the best visibility in the area, ranging from 10-30m with an average around 15m. Around the sites are vibrant, colourful reefs with thriving marine life. You can expect to see lots of juvenile fish, hard and soft corals, caves, schools of batfish, trevally (jacks) and barracuda, large cobia, angelfish, spotted sweetlips, groupers, a large number of stingrays, octopus, scorpionfish, cuttlefish, pufferfish, moray eels and schools of razorfish. Koh Prins (8 dive sites) The dive sites over three small islands and is situated around 5-6 hours off the mainland, about 3 hours south-west of Koh Rong Saloem. The best diving around this island is to the west and south and tends to be relatively shallow going to a depth of around 8-9m. Visibility ranges from 5-25m but is usually around 10m. Koh Russei (Bamboo Island) and Koh Takiev Near Sihanoukville coral is generally in good condition, and marine life includes a lot of smaller fish such as pipefish, anemone fish and gobies.