Ang Thong Marine Park in the Gulf of Thailand offers a diverse underwater environment featuring reefs, caves, and drift diving opportunities. Located 30 kilometres from the shore, the site requires boat access. Divers and snorkellers can explore depths ranging from 1 to 25 metres, with an average depth of 10 metres. Conditions are generally suitable for beginners, with mild currents and visibility fluctuating between 5 and 30 metres. Water temperatures remain warm throughout the year, typically between 28 and 31 degrees Celsius. Hazards to consider include boat traffic, variable visibility, and surf. Typical dives last approximately 60 minutes.

Ko Wao is a reef dive site in Ang Thong Marine Park, Thailand, accessible by boat from Koh Samui. The site features depths ranging from 5 to 30 metres, with an average depth of 13 metres, making it suitable for beginners who can explore the shallower sections. Conditions include mild currents and visibility between 5 and 25 metres. Water temperatures typically range from 28 to 31 degrees Celsius. The site supports a variety of reef fish and invertebrates. Divers should be aware of potential surge and jellyfish. Night diving is available at this location, and guided tours are recommended for those visiting for the first time.

Hin Yippon is a reef site in Ang Thong Marine Park, accessible only by boat. The reef structure extends from 5 metres to a maximum depth of 25 metres, with an average depth of 10 metres. Divers and snorkellers can explore anemones and soft corals in the shallows, while deeper sections feature sea fans, barrel sponges, and black corals. Conditions are variable, with visibility ranging from 3 to 20 metres and moderate currents that can strengthen quickly. Due to these conditions and the potential for nitrogen narcosis at depth, this site is suited to intermediate-level divers. Divers should remain close to the reef structure to maintain control in the current.

Southwest Pinnacle is a challenging dive site located 7400 metres from Koh Nang Yuan. The site consists of a series of pinnacles and walls rising from the seabed to a minimum depth of 5 metres, with the average depth around 20 metres. Due to strong, shifting currents and depths reaching 30 metres, this site is suited for advanced divers. Visibility is highly variable, ranging from 5 to 30 metres. Divers must maintain strict buoyancy control and monitor air consumption closely. Boat entry is required, and divers should plan their descent and ascent carefully relative to the current flow to remain near the structure.

Southwest Pinnacle is a series of submerged rock formations located near Koh Nang Yuan. The site features a complex topography of pinnacles, reefs, and walls that descend from 5 metres to a maximum depth of 30 metres, with an average depth of 20 metres. Access is by boat only, as the site is situated over 7 kilometres from the shore. Divers should be prepared for moderate currents and potential surge, which can impact visibility. Due to the depth and current conditions, this site is recommended for advanced divers. Typical dive times are approximately 50 minutes. Facilities available include boat charter services and parking at the departure point.

Koh Kong Kliang is a reef site located within Ang Thong Marine Park, offering depths between 6 and 14 metres with an average of 9 metres. This site is suitable for beginners and is accessible by boat only. The environment features mild currents and water temperatures ranging from 28 to 31C. Visibility is approximately 3 metres, requiring divers and snorkellers to move slowly and maintain awareness of the reef structure. Sharp coral and rock edges are present, so maintain a safe distance from the substrate to avoid injury. Night diving is permitted, and morning visits are recommended to maximise visibility before the water conditions change.

Southwest is a pinnacle dive site located 7000 metres from Koh Nang Yuan. The site features craggy overhangs and reaches depths between 5 and 30 metres, with an average depth of 22 metres. Divers should be prepared for moderate currents and potential strong current conditions. Visibility at the site is highly variable, ranging from 2 to 40 metres. Due to the depth and current, this site is best suited for intermediate divers. Access is by boat only, with typical dives lasting around 30 minutes. Hazards include strong currents and triggerfish. Water temperatures remain warm throughout the year, ranging from 28 to 31 degrees Celsius.

Haad Yao is a reef site located in Ang Thong Marine Park, Thailand, suitable for both beginners and snorkellers. The site features depths between 5 and 14 metres, with an average of 7 metres. Visibility ranges from 5 to 30 metres. Divers can access the site by boat or from the shore. Hazards include sea urchins on the seabed and sharp coral edges; visitors should shuffle their feet during entry and exit. Species recorded around this area include wrasses, butterflyfish, groupers, and anemonefish. Onshore facilities include parking, toilets, showers, and equipment rental. Night diving is permitted at this location.