Vietnam’s Island-Building Spree Set to Surpass China in South China Sea, Raising Tensions

In recent developments, Vietnam’s island-building activities in the South China Sea are set to surpass the area reclaimed by China in the disputed Spratly Islands, according to a new report from the Asia Maritime Transparency Initiative (AMTI).

Between 2025 and the present, Hanoi has been actively dredging and expanding eight features under its control within the island chain located in the southeastern quadrant of the South China Sea. This expansion is based on satellite imagery from MAXAR and Planet Labs, as outlined in the AMTI report.

The Spratly Island chain comprises over 100 small islands or reefs, with full claims by China, Vietnam, and Taiwan, along with partial claims by the Philippines, Malaysia, and Brunei (CIA World Factbook). China’s territorial assertions have garnered significant attention for more than a decade due to its land reclamation activities at several locations, leading to the construction of runways and military installations.

China asserts nearly all of the 1.2 million-square-mile South China Sea, a crucial shipping route transporting trillions of dollars annually, as its sovereign territory. This claim is based on the so-called Nine Dash Line, which has been previously ruled without legal basis by the Permanent Court of Arbitration in The Hague.

Compared to China’s vocal territorial claims, Vietnam’s have historically been less prominent, and its previous reclamation efforts have been less ambitious. Some of the reefs where current island-building activity is intense have long housed only small pillboxes, including Alison Reef, Collins Reef, East Reef, Landsdowne Reef, and Petley Reef, according to AMTI. New land is also being constructed at three features that underwent earlier rounds of reclamation – Amboyna Cay, Grierson Reef, and West Reef, the report states.

AMTI’s findings indicate that all 21 Vietnamese-controlled rocks and low-tide elevations in the Spratly Islands have now been extended with artificial land. The report further notes that Vietnam has created approximately 70% as much artificial land in the Spratlys as China, with the ongoing reclamation at these eight new features likely to match or even surpass Beijing’s island-building efforts.

Among the 21 features controlled by Hanoi, there are significantly more than those under Beijing’s control, according to AMTI. Additionally, military-related structures, including munitions depots, have been or are being built on seven other Vietnamese-controlled islands where reclamation work has largely been completed.

The recent report comes amid escalating tensions between China and the Philippines over South China Sea territory. Competitive claims by Beijing and Manila have grown increasingly contentious in recent years, resulting in violent confrontations between their coast guards involving water cannons and, in one instance, bladed weapons. Last month, a Chinese navy destroyer collided with a China Coast Guard ship as they harassed a Philippine Coast Guard vessel in contested waters north of the Spratlys near Scarborough Shoal, causing heavy damage to the bow of the China Coast Guard ship.

Analysts suggest that Beijing’s preoccupation with issues related to the Philippines may have provided Vietnam with an opportune cover for its aggressive island-building campaign. Collin Koh, a research fellow at the S. Rajaratnam School of International Studies (RSIS) in Singapore, stated, “For now, much of China’s bandwidth of attention is directed at the Philippines, and it would rather maintain a stable front with each of the other Southeast Asian rivals in the South China Sea.”

Ray Powell, director of SeaLight, a maritime transparency project at Stanford University’s Gordian Knot Center for National Security Innovation, echoed similar sentiments: “It seems that Beijing has calculated that keeping the Philippines isolated from the other South China Sea claimants is worth more right now than preventing Vietnam from making substantial territorial gains.”

While China maintains a significant edge in the South China Sea, it may not find Hanoi’s latest moves to be overly threatening. However, Koh warns that Beijing must not underestimate this advantage, noting the improving relations between Vietnam and the Philippines: “There’s been effort between Vietnam and the Philippines to come closer on maritime security cooperation, as evidenced by the recent bilateral coast guard exchanges and joint exercise. That should serve as a timely reminder to Beijing that Hanoi owns the Manila card of leverage.”