Weizhou Island sits in the Gulf of Tonkin, administratively part of Beihai in Guangxi. Beihai and the Leizhou Peninsula lie north and east, Xieyang Island to the southeast, Hainan farther south across open water, Vietnam to the west. The island covers 24.74 square kilometres and rises to 79 metres, roughly circular at about six kilometres east to west and 6.5 kilometres north to south. It is the largest island in Guangxi and is often described as China's youngest volcanic island.
Boats leave from Beihai. Schedules, landing arrangements and local access rules change with weather and season, so confirm current details with official sources before setting out.
The shape lava left
Weizhou is a basalt platform: a thick layer of purplish-red weathered basalt over a gently undulating surface. The south, particularly its eastern and western flanks, is highest at about 75 metres; the land tilts north toward Beigang, dropping to roughly 20 metres before running out into broad sand. The southern half of the coast is erosional, with cliffs, caves, platforms and stacks. The north is depositional: sand ridges, lagoons, beaches and reef flats. Two different coastlines within a short ride.
The island records repeated basaltic eruptions, later subsidence and uplift, storms, earthquakes and a long contest between sea and rock. The low profile is deceptive. The geology is legible in the shoreline, especially where the sea has cut into old volcanic rock.
Nanwan: cliffs, caves and a flooded crater
Nanwan is the clearest place to read the island's geology. The bay started as a volcanic hollow open to the south; the sea flooded it, leaving a bay ringed by volcanic sedimentary rock. Waves and tides cut layered sea caves at the base of the rock. When the rock above loses support it fractures and falls away, and steep cliffs are what remain. Along the roughly five-kilometre bay between the eastern and western flanks, cliffs stand 30 to 50 metres high on slopes steeper than 75 degrees. The old crater is now a deep-water harbour, with an arc-shaped wall 50 to 80 metres high still readable in the landform.
At the foot of retreating cliffs, erosion platforms remain. On the platform below Pig Islet, on the east side of Nanwan, volcanic bombs and impact pits sometimes show; waves roll the bombs and grind debris, widening hollows into potholes. Resistant rock left standing becomes a sea stack, and Pig Islet is one: about 35 metres high, under 30 metres wide and roughly 100 metres long.
North shore: beaches and reef flats
The northern beaches are broad and flat, generally 150 to 300 metres wide. Sand and gravel lie four to eight metres thick over basalt, with bedrock showing at some breaks. The intertidal zone can reach 150 metres across. Below it, a subtidal band about 60 metres wide carries coral, with reef flat beneath. Fragments broken by waves mix with shell and gravel and can cement into beach rock; at Beigang, beach rock runs from an old lagoon to the upper subtidal zone, over basalt.
These are working coasts, not static scenery. Tides and storms rearrange them, and small features such as potholes or exposed rock shift from season to season. Don't walk on coral, and don't take shells, rocks or other coastal material.
Scenic areas and village landmarks
The island's named scenic areas are Crocodile Mountain, Dishuidanping, Shiluokou, the Catholic Church and Wucai Beach. They are spread around the island and cover different ground: coastal viewpoints and shoreline, plus one of Weizhou's best-known built landmarks in the church. Beigang, in the north, is a useful reference point for the change from basalt to beach.
Group nearby stops instead of crossing the island repeatedly. Access to individual sites depends on weather, tides and local conditions, so check locally rather than assuming every path or shoreline section is open.
Practicalities
Weizhou is small, but the coast rewards a slower stay. The same cliff or beach reads differently at low tide and in evening light, and the south's rock forms have little in common with the flat north. Marine weather is the main variable: boats can be disrupted, so leave a buffer and confirm forecasts, schedules and local rules with official sources.
Much of the island's interest is geological and coastal, so a rushed circuit gives you less than a focused walk or a day split between Nanwan and the north shore. Carry water and sun protection, stay on established paths where they exist, and treat the villages and the church as places where people live and worship rather than backdrops.
How this guide was made
This guide combines structured research and automation with source and duplication review. Dates change; verify time-sensitive details before travelling.