beginner
    (38)

    Koh Preus (Harbour Reef) – Sihanoukville – Coastal & Nearshore Reefs Dive Site

    14m Max
    5-15m Vis
    boat

    Site Overview

    Koh Preus (Harbour Reef) is a gently sloping coral at 5 to 14 metres home to stingrays, moray eels, and large schools of snappers in accessible nearshore waters dive site in the Sihanoukville – Coastal & Nearshore Reefs region of Cambodia, situated among the diverse reef systems and island formations that make this Southeast Asian nation one of the Gulf of Thailand's most emerging diving destinations. The site features depths from 5 to 14 meters with an average depth of 10 meters, offering an extraordinary underwater experience showcasing the remarkable combination of fringing reefs, offshore islands, and historical wrecks that Cambodia's waters are celebrated for among adventurous divers seeking less-crowded tropical diving. Renowned for its encounters with Stingray, Moray Eel, Snapper and other remarkable marine species, Koh Preus (Harbour Reef) attracts divers seeking thrilling underwater adventures in one of Southeast Asia's most distinctive and developing diving destinations. The Cambodian coast creates a fascinating underwater landscape of fringing reefs, rocky islands, artificial reef structures, and natural coral communities that provide habitat for diverse marine life in the warm waters of the Gulf of Thailand. The unique geography of Cambodia's coastline with its chain of offshore islands creates varied habitats supporting abundant marine life including tropical reef fish, sharks, rays, and pelagic visitors found in few other destinations. Visibility typically ranges between 5 and 30 metres depending on site location and season with the outer island sites offering the clearest water. Water temperatures range from 26 to 31 degrees Celsius year-round making a 3mm shorty standard equipment. Koh Preus (Harbour Reef) consistently ranks among the top dive sites in the Sihanoukville – Coastal & Nearshore Reefs region, drawing dedicated divers who seek exceptional reef diving experiences combining rich marine biodiversity with the excitement of exploring Cambodia's developing underwater frontier.

    Dive Briefing

    "A typical dive at Koh Preus (Harbour Reef) begins with entry from the dive boat, descending to the main formation at approximately 10 meters while orienting yourself and equalizing before exploring the remarkable Cambodian underwater landscape. Once established on the main formation, divers should swim along the reef structure or wreck exploring diverse habitats, moving between coral encrustations, swim-through sections, and sandy areas while maintaining excellent buoyancy control to protect the marine life colonising the structure below. The most productive depth zone is between 5 and 9 meters where the highest concentration of reef fish species and photographic opportunities are abundant. Navigate along the reef or wreck edge watching for pelagic species in the surrounding water, and check the overhangs, crevices, and ledges where moray eels, groupers, and larger reef fish shelter from the current. Cambodia's reef and wreck environments require careful awareness of marine life hazards and potential entanglement when exploring interior sections. Monitor depth and NDL particularly near 14 meters on the deeper sites, and always maintain a conservative approach to dive planning given the distance to the nearest hyperbaric facilities. Scan the surrounding water for approaching pelagic species including eagle rays and barracuda that patrol the reef edges. Conclude the dive with a slow ascent and a generous safety stop at 5 meters, deploying your DSMB before surfacing and signaling the dive boat for pickup."

    Signature Marine Life

    Stingray

    high

    Taeniura lymma

    Best: November, December, January

    Moray Eel

    very high

    Gymnothorax sp.

    Best: November, December, January

    Snapper

    very high

    Lutjanus sp.

    Best: November, December, January

    Lionfish

    very high

    Pterois miles

    Best: November, December, January

    Butterflyfish

    very high

    Chaetodon sp.

    Best: November, December, January

    Bannerfish

    very high

    Heniochus sp.

    Best: November, December, January

    Soft Coral

    very high

    Dendronephthya sp.

    Best: November, December, January

    Anthias

    very high

    Pseudanthias sp.

    Best: November, December, January

    Safety & Hazards

    • Variable visibility from 5 to 20 metres near the coast due to sediment runoff requiring careful buoyancy and buddy awareness
    • Marine life hazards including lionfish, stonefish, and fire coral requiring careful hand placement on reefs and wrecks
    • Boat traffic in Sihanoukville harbour and coastal shipping channels requiring DSMB deployment and surface awareness
    • Moderate currents at some offshore sites requiring drift diving awareness and DSMB deployment
    • Hot tropical climate requiring hydration management and sun protection between dives
    Nearest Chamber
    Sihanoukville Provincial Hospital (limited hyperbaric)
    10km away

    Traveler Notes

    Who is this for?

    Koh Preus (Harbour Reef) is suitable for Open Water certified divers comfortable with the depth profile and conditions at this Cambodian location. The site rewards beginners with abundant marine life, manageable conditions, and excellent opportunities for building confidence in a warm tropical marine environment. Underwater photographers will find outstanding opportunities with diverse marine species and dramatic reef or wreck structures in the shallower sections. The relatively sheltered environment makes this an ideal introduction to reef and wreck diving for newly certified divers, with the conditions providing a comfortable and confidence-building experience in one of Southeast Asia's most distinctive diving destinations.

    cambodia
    reef
    harbour
    snapper
    stingray
    beginner

    Quick Stats

    Difficultybeginner
    CertificationOpen Water
    Currentlight
    Water Temp27-31°C
    Best TimeNovember - April

    Dive Logistics

    Operators
    • Scuba Nation Diving Centre
    • Chez Claude Dive Center
    • Cambodia Dive Shop
    Pricing Guide
    $50 - $90
    Per 2-tank boat dive

    Photography Info

    Recommended Gear
    16-35mm
    60mm macro
    100mm macro

    Best for: wide_angle, macro

    Nearby Stay

    Sokha Beach Resort

    Sihanoukville5km away

    Check Availability

    Sahaa Beach Resort

    Otres Beach8km away

    Check Availability