Vietnam is building islands to challenge China’s hold on a vital waterway

Contested South China Sea boasts rich oil and gas reserves and could play key role in a conflict over Taiwan

In the turquoise waters of the South China Sea, one country is challenging Beijing’s grip on one of the world’s most important maritime thoroughfares.

Over four years, Vietnam has built out a series of remote rocks, reefs and atolls to create heavily fortified artificial islands that expand its military footprint in the Spratly Islands, an archipelago where Hanoi’s claims clash not only with China’s but also with those of Taiwan, the Philippines, Malaysia and Brunei.

Built from sand, coral and rock carved from the bottom of the sea, the new islands now sport multiple ports, a 2-mile-long airstrip to accommodate large military aircraft, ample munitions storage and defensive trenches that could host heavy weaponry, according to satellite images reviewed by The Wall Street Journal and analysts who study the South China Sea.

Island race

Vietnam’s outposts allow it to project power in the Spratlys and are a response to China’s own campaign to expand and fortify a series of rocks and atolls in the same island chain. The Vietnamese militarization of the islands far surpasses what any country other than China has undertaken in the South China Sea, a key thoroughfare for global trade that would be a vital resupply route for the U.S. military should a conflict break out over Taiwan.

Satellite images show that Vietnam has created new land on all 21 rocks and so-called low-tide elevations—reefs that were previously submerged at high tide—that it occupies in the Spratlys. That compares with China’s seven such artificial islands in the archipelago.

As of March, Vietnam had built more than 2,200 acres of artificial land in the South China Sea, compared with just under 4,000 acres constructed by China, according to the Washington-based Center for Strategic and International Studies, or CSIS.

In the 1970s and ’80s, China forcibly seized from Vietnam several features in the Spratlys and the Paracel Islands, another disputed archipelago further north, in battles that claimed the lives of dozens of Vietnamese troops.

More recently, China took control of Scarborough Shoal from the Philippines in 2012, raising fears among other countries in the region, including Vietnam, that China could do the same to them. Beijing also has pressured Hanoi to cease oil-and-gas exploration in waters it considers its own and challenged Vietnamese fishermen’s access to the Paracels.

How to build an island

Vietnam began reclaiming land on a large scale in 2021, when huge dredging barges appeared near several reefs and rocks in the Spratlys.

Vietnam also employs land-based excavators that lift material from closer to the shore to expand the island surface. The new landmass is then fortified with rock and concrete walls to protect it from erosion.

The scale of transformation can be seen on Sand Cay, which in a matter of years grew from a fleck of an island with a handful of buildings into an expansive outpost with a large, fortified port and other military infrastructure.

China has used its fortified islands in the South China Sea to deploy vessels and aircraft for longer periods without having to refuel and restock on the mainland. It has also installed extensive radar and other surveillance infrastructure that give it visibility of other countries’ movements across the waterway.

Vietnam is expected to make similar use of its new outposts, albeit without directing aggressions against other countries, says Harrison Prétat , deputy director of CSIS’s Asia Maritime Transparency Initiative.

A base for critical infrastructure

Barque Canada Reef, Vietnam’s largest and most sophisticated artificial island in the South China Sea, illustrates major new facilities and their purpose.

Other islands built out by Vietnam feature many of the same installations, including ports, ammunition storage and the larger administrative buildings or barracks.

The Vietnamese government hasn’t publicly addressed its artificial island building, although officials have said that the country is focused on protecting its sovereignty in the South China Sea. Spokespeople for the Vietnamese and Chinese foreign ministries didn’t respond to requests for comment.

When asked in February about Vietnam’s land reclamation, a spokesman for the Chinese government said that it opposes “construction activities on illegally occupied islands and reefs.”

However, Chinese forces never sought to prevent Vietnamese dredgers from accessing the outposts. That contrasts with China’s aggressive rhetoric and actions against the Philippines, whose vessels it has repeatedly blocked from taking supplies to its more modest outposts in the South China Sea.

Milder response

The strikingly different treatment can be explained by Vietnam’s more complex relationship with China, says Khang Vu , a visiting scholar at Boston College. Chinese companies own thousands of factories in Vietnam, from where they export to the U.S. and other countries that have placed higher tariffs on China. The two nations’ ruling Communist parties have also established ways to tackle issues, such as Chinese aggressions against Vietnamese fishermen in the Paracels, out of the public eye.

“Vietnam wants to manage the dispute with China, but at the same time we want to prevent another Chinese surprise attack against those islands,” says Vu.

By contrast, Beijing views the Philippines, a U.S. treaty ally, as a proxy for Washington, whose presence in the South China Sea Beijing opposes. The U.S., which has condemned China’s island-building, hasn’t publicly spoken out against Vietnam’s efforts, likely because they are seen as a potential bulwark against Beijing, says Le Hong Hiep , a senior fellow at the ISEAS–Yusof Ishak Institute in Singapore.

A State Department official said the U.S. calls “on South China Sea claimants to resolve their disputed claims to territory peacefully in accordance with international law.”

Few analysts believe that Hanoi, with its much smaller navy and air force, could actually defend the outposts during an all-out war. That relative weakness also helps explain why other countries in the region have mostly looked the other way on Vietnam’s large-scale creation of artificial land that can be seen here:

“China’s island building represented a direct threat to a lot of Southeast Asian economic interests, the access to the waters, and…also was a threat to navigation and international maritime rights,” says Boston College’s Vu. “I don’t think that anyone thinks that Vietnam is going to do any of that.”

By Gabriele Steinhauser & Emma Brown & Ming Li – The Wall Street Journal – November 14, 2025