Guandongshi is a reef and wall site located on the outer reef of Lanyu. The topography features a wall dropping from 15 to 45 metres, with an average depth of 30 metres. This site requires boat access and is suited for intermediate divers with drift-diving experience. Conditions include strong, shifting currents and visibility ranging from 20 to 50 metres. Divers should be aware of sharp coral and rock edges, necessitating good buoyancy control. Due to the strong flow, timing descents for slack water or the early incoming current is recommended. An Advanced Open Water certification or equivalent is required to navigate this site safely.

DongQing Bay on the eastern shore of Lanyu features a reef and drop-off topography accessible directly from the shore. The reef starts at approximately 5 metres, transitioning into a drop-off that extends to 30 metres. With visibility ranging from 20 to 50 metres, the site is suitable for intermediate divers. Water temperatures remain between 25 and 29 degrees Celsius. Divers should be aware of moderate currents that can strengthen unexpectedly, making slack water around the tide turn the most manageable time for entry. Night diving is permitted. On-site facilities include parking, toilets, showers, changing rooms, a rinse station, air fills, and equipment rental.

Shell Sand in Lanyu, Taiwan, features a combination of open reef and a blue hole. The site is suitable for beginners, with depths ranging from 5 to 20 metres and an average depth of 15 metres. Divers and snorkellers can expect mild currents and high visibility, typically between 30 and 50 metres. Water temperatures remain warm throughout the year, ranging from 25 to 30 degrees Celsius. Entry is possible via both shore and boat. Hazards include the presence of stonefish on reef structures and the potential for sharks in the area. Always follow boat captain instructions for entry and exit.

Junjianyan off Lanyu, Taiwan, features a diverse topography comprising a reef top, wall, and drop-off that descends to 35 metres. Visibility is excellent, ranging from 20 to 50 metres, allowing for clear views of the vertical structure. This site is accessible only by boat and is suited for intermediate divers due to strong currents. Water temperatures remain between 25 and 29 degrees Celsius throughout the year. Hazards include jellyfish, sharks, and significant currents. Divers should exercise caution regarding overhead environments and follow local guidance on tidal windows to manage current exposure. Night diving is permitted with prior arrangements.

Kaiyuan Old Port is a shore-entry site in Lanyu, Taiwan, featuring a diverse topography of reefs, caves, and drop-offs. Located 300 metres from the shore, the site reaches depths between 13 and 34 metres, with an average depth of 15 metres. Divers and snorkellers can expect visibility ranging from 30 to 50 metres. Conditions are variable, with strong currents, surge, and potential boat traffic, making this site suitable for advanced divers. Facilities at the location include parking, toilets, showers, changing rooms, and a rinse station. Guided tours and boat charters are available through local dive shops.

Green Field is a boat-access dive site off Lanyu, Taiwan, characterised by shallow reef terrain. The site features a wall that extends to 70 metres, requiring divers to monitor their depth gauge closely. Conditions are variable, with strong currents that can shift quickly and push divers off the reef. Marine life recorded at the site includes wrasses, groupers, Pacific Orange-spine Unicornfish, rock cod, Powder-blue Surgeonfish, Striped Surgeonfish, Bird Wrasse, Moorish Idol, Indo-Pacific Sergeant Major, hawkfish, Lined Bristletooth, and snails. Due to the potential for strong currents and the depth of the wall, this site is suitable for intermediate divers who possess strong buoyancy control.

Shuangshityen is a complex site off the coast of Lanyu, Taiwan, featuring a combination of reef, drop-off, and cave topography. Divers encounter depths ranging from 11 to 19 metres, with an average of 13 metres. The site is defined by strong currents, requiring advanced certification and solid buoyancy control. Visibility is excellent, typically between 30 and 50 metres. Access is strictly by boat, and surface conditions often include significant surf and swell. Divers should time their entry around slack water to manage the current. The cave system presents an overhead environment, necessitating careful navigation. Due to the challenging conditions and depth, this site is suited for experienced divers only.

Mujiyan is a reef site located 200 metres off Lanyu, Taiwan, featuring depths ranging from 1 to 20 metres with an average of 10 metres. The site offers visibility between 20 and 50 metres in water temperatures of 25 to 30 degrees Celsius. Access is possible via shore or boat, though divers must navigate sharp coral and potential surf. Due to variable currents that can strengthen without warning, careful planning and local advice are recommended. Species recorded around this area include sea kraits, clown triggerfish, regal angelfish, blackback anemonefish, and various wrasses. Divers should maintain buoyancy control to avoid contact with the reef structure.