How China secretly built brand new islands by pouring millions of tons of sand

What happens when a nation decides to conjure new islands—by pouring sand into the sea? In Southeast Asia, China has achieved just that over the past twelve years, drastically altering both the waterscape and regional politics. The scale of this ongoing effort, involving millions of tons of dumped sand and a wave of construction, has left observers equal parts fascinated and uneasy. Here’s how China built islands out of the ocean in one of the world’s most contested waterways—and why the effects reach far beyond the shore.

From Seafloor to Artificial Islands: A Monumental Campaign

The massive transformation began in late 2013, when China launched a sweeping effort to reclaim seven coral reefs in the Nansha and Xisha archipelagos—known internationally as the Spratly and Paracel Islands. Between December 2013 and June 2015, China completed the first phase of this operation: in less than 20 months, the country created more than 4.6 square miles of artificial land, according to the US-China Economic and Security Review Commission. For comparison, that’s 17 times more territory than all other Southeast Asian nations combined managed to claim in the previous forty years.

Since 2015, Beijing has moved beyond reclamation and focused on fortifying these new islands. The newly built land features runways, hangars, military ports, radar installations, and a steady stream of construction. Satellite images—for example, via Google Earth archives—vividly document the dramatic changes above and below the surf, showing how the islands have taken on a military character.

How China Built Islands from the Ocean

China’s method is straightforward, but the scale is enormous. Construction crews first excavate the coral seabed, then use dredgers to pump sediment from shallow waters onto the reefs. The material is deposited in layers, stabilized by retaining walls. Massive compactors and excavators firm up the ground, creating a stable foundation. Only then do construction teams pave surfaces, lay roads, and build runways suitable for both civilian transport and military aircraft.

Satellite time-lapse imagery shows the islands rapidly emerging from once-empty water—compelling evidence of a transformation both impressive and concerning.

On these man-made lands, China has erected airstrips, military ports, radar stations, and, according to Western analyses, may have constructed underground facilities and missile launch areas. These installations allow China to project strength and maintain a sustained presence in disputed parts of the South China Sea.

A Question of Motive: Rescue Bases or Military Outposts?

China officially promotes these islands as intended for peaceful purposes: supporting maritime rescue, fishing, scientific research, safer navigation using radars, and meteorological data collection. The government asserts that any military use would be for defense if necessary.

Regional neighbors are deeply skeptical. Vietnam, Taiwan, Japan, and the Philippines view this island-building as a unilateral move by China to cement sovereignty over contested waters. Japan’s Ministry of Defense, in particular, has warned that these bases could enable China to establish a permanent and offensive force in the southern seas.

Recent assessments from the Center for Strategic and International Studies (CSIS), published in 2025, support the view that China’s near-constant operational reach in the region relies on these artificial islands—an engineering drive launched over a decade ago. Analysts in the US and elsewhere report the infrastructure can accommodate military jets, warships, underground facilities, and possibly missile platforms.

Vietnam, too, has followed China’s lead since 2013, reinforcing its own reefs by dumping sand—fueling a rapid, competitive race to create new land, which has only intensified the region’s political tensions.

An Environmental Cost: Damaged Coral and Disrupted Ecosystems

Beyond the battle for influence lies a grim environmental toll. Estimates indicate that between 4.6 and 7 square miles of coral reefs—previously among the healthiest in the region—have been destroyed by this activity. Plumes of sediment from the work travel far beyond the construction zones, disrupting ocean currents and sediment cycles, and harming ecosystems well outside the immediate area.

Even Chinese scientific reports acknowledge the damage: marine life has been wiped out in affected areas, with consequences spreading across ecosystems. China’s own Oceanic Administration denies that the island projects are to blame, stressing that all undertakings are carefully assessed for environmental impact. Instead, Chinese authorities point to ocean acidification and climate change as the real threats to marine life.

Shifting Sands Have Lasting Consequences
China’s dramatic reshaping of the seafloor has redrawn not only maps, but regional power equations. Impressive as the logistics and engineering may be, these artificial islands prompt tough questions about sovereignty, the future of the area, and the fate of its threatened marine environments. Building new ground at sea may settle some disputes on paper, but brings new risks and unresolved consequences for the waters—and life—beneath the waves.