Sai Daeng Beach is a shore-access reef site located on Koh Nang Yuan, Thailand. The site features a shallow average depth of 4 metres, ranging between 2 and 6 metres, making it suitable for beginners and snorkellers. Divers and snorkellers can observe a variety of marine life, including common sightings of Titan Triggerfish, wrasses, Longfin Bannerfish, Golden Butterflyfish, and Blue-barred Parrotfish. Uncommon species recorded here include Bluespotted Fantail Ray, Blue Ringed Angelfish, Pink Skunk Anemonefish, and Blacktip Grouper. The site offers visibility between 10 and 30 metres with mild currents, though users should remain aware of potential strong currents. Facilities include parking, toilets, equipment rental, and a cafe.

Aow Leuk is a wide, shallow bay located on the east side of Koh Tao. The site features a sandy bottom, natural coral reefs, and artificial reef projects consisting of concrete block sculptures. Divers and snorkellers can explore depths ranging from 5 to 15 metres, with an average depth of 8 metres. The site is suitable for beginners and accessible by both boat and shore. Visibility typically ranges from 5 to 20 metres, and currents are generally mild. Facilities available at the site include a cafe, restaurant, toilets, equipment rental, and accommodation. Night diving is permitted, with typical dives lasting 45 minutes.

Laem Thian is a diverse marine site featuring a combination of reef, cave, and drop-off topography. Located near Koh Nang Yuan, the site offers depths ranging from 5 to 24 metres with an average of 15 metres. Access is exclusively by boat. Divers and snorkellers should be prepared for moderate currents and potential surge, as well as deep water. Visibility at the site typically fluctuates between 10 and 30 metres. Water temperatures are consistent, ranging from 28 to 31 degrees Celsius throughout the year. Due to the prevailing conditions and depth, this site is best suited for intermediate-level divers.

Shark Island is a surface-breaking pinnacle located 300 metres off the southern tip of Koh Tao. This site features a mix of reef, drift, and artificial reef topography, descending to a maximum depth of 28 metres with an average of 14 metres. Due to its location, the site experiences strong currents and variable visibility ranging from 3 to 30 metres. Divers and snorkellers may encounter wrasses, golden butterflyfish, and blue-barred parrotfish, alongside less frequent sightings of bluespotted fantail rays, titan triggerfish, and harlequin sweetlips. Access is by boat only. Hazards include strong currents, down currents, and sharp coral. Thermoclines can occasionally reduce water temperatures from the typical 28 to 31 degrees Celsius down to 24 to 25 degrees Celsius.

King Kong Rock is a reef and artificial reef site located 500 metres off the coast of Koh Nang Yuan. The site features depths ranging from 5 to 30 metres, with an average depth of 14 metres. Access is exclusively by boat, and the site is suited for intermediate divers. Conditions typically include mild currents and visibility between 10 and 25 metres. Water temperatures remain warm throughout the year, ranging from 28 to 31 degrees Celsius. Divers should be aware of potential hazards, including jellyfish and stonefish. A typical dive at this location lasts approximately 45 minutes.

Shark Bay at Koh Nang Yuan is a shallow reef and seagrass site suitable for both diving and snorkelling. The site features depths ranging from 3 to 8 metres, with an average depth of 5 metres. Access is via the shore, and conditions are generally mild, though visibility can fluctuate between 5 and 30 metres. The area is well-suited for beginners and supports night diving. Facilities available at the location include parking, toilets, and a cafe. Divers and snorkellers should remain aware of potential hazards, including boat traffic, jellyfish, and sharp coral.

Lang Khaai Bay at Koh Nang Yuan provides a sheltered reef environment suitable for beginners. The site features a mix of hard and soft corals, alongside a cave and cavern system. Depths range from 5 to 23 metres with an average of 15 metres. Visibility typically spans 10 to 25 metres, supported by mild currents. Divers may access the site via shore or boat. Due to the presence of sharp coral and rocks, as well as overhead environments within the cave and cavern, careful buoyancy control is required. On-site parking is available for convenience.

Freedom Beach is a shallow reef located at the southern tip of Koh Nang Yuan. Divers and snorkellers can access this site directly from the shore. The reef, situated near Buddha Rock, reaches depths between 2 and 14 metres with an average of 7 metres. Conditions are generally mild, though visibility fluctuates between 5 and 20 metres. Marine life frequently observed includes Titan Triggerfish, Longfin Bannerfish, Golden Butterflyfish, and Blue-barred Parrotfish. Divers may also encounter Bluespotted Fantail Rays, Blue Ringed Angelfish, and various wrasses. Hazards at this site include jellyfish, sharks, and sharp coral. Facilities available include toilets, showers, and gear storage.