Vietnam Expands Spratly Outposts With New Harbors, Defenses and a Runway

A larger Vietnamese presence takes shape

Vietnam has expanded its reclaimed land in disputed parts of the South China Sea to more than 3,000 acres, with estimates from early 2025 putting its total at roughly 70 percent of the artificial land China created during its major construction campaign between 2013 and 2017. Across the Spratly Islands, small concrete positions are becoming larger outposts with harbors, helipads, storage facilities and coastal defenses.

Barque Canada Reef, now Vietnam's largest artificial outpost by land area, stretches more than four kilometers. Satellite imagery from late 2024 showed a runway roughly 8,000 feet long taking shape there. Eight other outposts have gained harbors during the expansion, bringing Vietnam's network to three times the four harbors it had before 2021.

Vietnam's building campaign has accelerated since 2021, following years of more restrained activity. By December 16, 2025, its construction effort had reached all 21 reefs and low tide elevations that it occupies. These are part of a wider network of Vietnamese holdings in an archipelago also claimed, in whole or in part, by China, the Philippines, Malaysia, Brunei and Taiwan.

Hanoi is turning isolated positions into places where its navy, coast guard and maritime militia can remain farther from the mainland for longer. Maritime militia vessels can support a government's presence at sea alongside its regular forces. Harbors and supplies close to patrol areas reduce the need for repeated journeys home.

Vietnam has long balanced its defense needs with diplomatic caution. Larger platforms strengthen its physical presence without requiring frequent confrontations at sea. They also support fishing communities and make an attempt to dislodge Vietnamese forces more costly. Sovereignty remains disputed, while the practical balance of ships, supplies and infrastructure is changing.

How the construction campaign spread

Vietnam's reclamation work, which creates land by depositing material on submerged or partly exposed features, has proceeded in waves. Modest activity earlier in the decade accelerated in 2023 and surged in 2024. Satellite analysis identified hundreds of acres of new land during late 2023 and the first half of 2024, taking the country's reclaimed area into the thousands of acres.

Vietnam's footprint was only a fraction of China's a few years earlier. The estimate of more than 3,000 acres by early 2025, roughly 70 percent of China's output, shows how quickly that gap narrowed. Land area is one measure of the buildout; the facilities placed on that land determine how useful each position becomes.

Since the start of 2025, dredging and landfill have reached eight features untouched during the current construction round. Alison Reef, Collins Reef, East Reef, Landsdowne Reef and Petley Reef are among them. Small concrete posts at these locations have been expanded into actual landmasses. Expansion also resumed at Amboyna Cay, Grierson Reef and West Reef.

All 21 Vietnamese occupied reefs and low tide elevations now include artificial land. A low tide elevation is a feature exposed when the tide falls but submerged when it rises. Many of these positions had only limited structures four years earlier.

The main stages of the expansion are:

• Since 2021: Vietnam accelerated the transformation of small positions into larger outposts.
• Late 2023 and the first half of 2024: Satellite analysis recorded hundreds of acres of new land.
• During 2024: Barque Canada Reef expanded sharply, with runway construction advancing late in the year.
• Early 2025: Estimates placed Vietnam's total reclaimed area above 3,000 acres.
• Since the start of 2025: Work reached eight additional features, completing the spread of artificial land across all 21 occupied reefs and low tide elevations.

Harbors become the center of the network

Vietnam has devoted a large share of its landfill effort to maritime logistics, the work of moving and storing supplies needed to keep vessels operating. Eight recently expanded outposts have gained harbors. Before 2021, only four Vietnamese features in the Spratlys had them, so the additions triple the number to 12.

The expanded harbor network includes Barque Canada, Ladd, Central, Namyit, Pearson, Sand Cay, South Reef and Tennent. Ships can use these positions to refuel, take on supplies and shelter from bad weather without returning to the mainland. More local support also helps sustain patrols around fishermen and energy exploration activities facing harassment.

Discovery Great Reef, South Reef, Namyit Island, Pearson Reef, Ladd Reef and Tennent Reef have received extensive landfill since late 2023. Crews have cut access channels, dredged berths and raised platforms for docks and boat ramps. Temporary helipads have appeared at several features, while trenches and coastal defenses line new shorelines.

Central Reef and Tennent Reef have new piers and protected basins that indicate plans to accommodate a steady flow of government and maritime militia vessels. A protected basin gives boats a more sheltered place to berth than an exposed shoreline.

China gained a similar logistical advantage after completing its large artificial islands in the mid-2010s. Its piers, radar installations and runways support patrols around the clock. Vietnam's additions bring more of that local support to its own network, helping vessels spend more time near contested waters and less time traveling for supplies.

Barque Canada's runway and repeated building plans

Barque Canada Reef stands out for both its size and its developing airfield. Its expansion during 2024 produced an outpost more than four kilometers long, with imagery showing a runway of roughly 8,000 feet under construction late that year.

Vietnam's only existing Spratly runway is on Spratly Island. That strip is shorter and limits the types of aircraft that can operate there. A longer runway at Barque Canada would allow larger transport planes and surveillance aircraft to operate closer to disputed waters, improving response times and the length of patrols.

Satellite imagery also shows repeated patterns of military infrastructure across the expanded outposts. Several have hardened storage depots, often with six munitions containers inside protective blast walls. Those walls are intended to limit damage from an explosion. Hardened storage also suggests that fuel or ammunition can be kept locally.

Another recurring layout consists of six medium buildings arranged along three sides of a central courtyard, usually facing the sea. The pattern appears on several islands, and Barque Canada has multiple sets. Together, these arrangements suggest a standard approach to accommodation, garrison facilities and storage.

The placement of depots and buildings occupies corridors that might otherwise accommodate runways on long features such as Ladd, Pearson, Tennent and South Reef. Barque Canada is therefore likely to remain Vietnam's only new airfield in the chain for now. A date for bringing its runway into service has not been given.

Why these small features carry large stakes

The Spratlys lie across routes connecting Northeast Asia and Southeast Asia with the Indian Ocean and the Pacific. Commercial vessels carry energy, manufactured goods and raw materials through the South China Sea, supporting major economies far beyond the countries contesting its islands and reefs.

Fishing grounds provide an important source of protein for regional communities. Potential oil and gas reserves beneath the seabed add another reason governments seek access to the waters. Control of outposts affects where they can deploy patrols, support vessels and maintain bases.

Vietnam's expansion gives it a broader foothold in this crowded maritime area. Piers, shelters, lighthouses and safer harbors can serve fishermen and personnel facing strong storms, while also supporting military operations. Hanoi presents its improvements as necessary to safeguard people and withstand severe weather.

What international law says about new land

The United Nations Convention on the Law of the Sea sets rules for maritime claims. It distinguishes between islands, rocks and low tide elevations because their natural condition affects the maritime zones they can generate. An exclusive economic zone is an area where a coastal state has specified rights over resources.

Reclamation leaves a feature's legal category unchanged. Adding sand, concrete and buildings to a rock or reef does not create new exclusive maritime zones. Vietnam's projects strengthen its administrative and military presence while the underlying sovereignty and maritime claims remain in dispute.

A 2016 arbitral ruling in the case involving the Philippines and China found that China's sweeping claims, depicted by its nine dash line, had no legal basis under the convention. China rejects the ruling. Its broad claims cover almost the entire South China Sea, including areas contested by other governments.

Vietnam, the Philippines, Malaysia, Brunei and Taiwan also claim features in the Spratly chain. Larger outposts can help a government maintain a visible presence, but resolving the competing claims remains a separate legal and diplomatic task. In daily encounters, access and enforcement depend heavily on the forces present and the restraint they exercise.

Hanoi's stated safety rationale and its strategic needs meet in the same facilities. A harbor offers storm shelter and a place to supply patrol vessels. Storage buildings help sustain personnel and military operations. Sensors and defensive positions can be installed on the enlarged platforms. These overlapping civilian and military roles shape how neighboring governments and outside partners respond.

China objects while concentrating on the Philippines

China has spoken more forcefully about Vietnam's construction. In February 2025, its foreign ministry protested work at Barque Canada Reef, which Beijing places within what it calls the Nansha Islands. The ministry described the projects as construction on islands and reefs that China regards as illegally occupied.

Chinese Foreign Ministry spokesperson Guo Jiakun addressed Vietnam's work at a regular briefing. Restating Beijing's claim to the Spratlys, he warned against construction by other countries:

The Spratly Islands are China's inherent territory. China firmly opposes relevant countries construction activities on illegally occupied islands and reefs and will take necessary measures to safeguard its territorial sovereignty and maritime rights and interests.

China's response on the water has nevertheless been limited compared with its confrontations with the Philippines. Chinese coast guard and maritime militia vessels have harassed Philippine resupply missions at Second Thomas Shoal and increased pressure near Scarborough Shoal.

Collin Koh, a research fellow at the S. Rajaratnam School of International Studies in Singapore, said Beijing's concentration on the Philippines, a United States ally, helps explain the space Vietnam has had to build. He described China's interest in keeping relations with other Southeast Asian claimants stable:

For now much of Chinas 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.

Koh's assessment points to China's incentive to avoid pushing Vietnam closer to other claimants or outside powers. Ray Powell, director of SeaLight at Stanford University, similarly argued that Beijing was accepting Vietnam's quiet consolidation while prioritizing the isolation of Manila:

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.

Vietnam's construction has continued in that diplomatic setting, with limited public statements about its strategy and few dramatic announcements. Beijing's objections remain firm, even while its most visible maritime confrontations have centered on Philippine positions.

Stronger defenses within an unequal military balance

Vietnam's new outposts improve its ability to operate persistently, but China retains a large advantage in ships and technology. The People's Liberation Army Navy and China Coast Guard field far more vessels. China's maritime militia can also send large fleets of trawlers with steel hulls into contested areas.

Vietnam's fleet modernization has slowed, and its forces must cover a long coastline as well as an extended archipelago. Local harbors help stretch those resources by cutting travel time and improving access to maintenance, medical support and supplies. Expanded land also provides positions for more radar and coastal defense systems.

Trenches, revetments and coastal artillery emplacements point toward a strategy of denying an opponent easy access. Revetments are protective barriers around positions or equipment. These defenses improve the chances that personnel and facilities can survive an attack, while hardened storage keeps essential supplies nearby.

Barque Canada's airstrip would add airlift and maritime patrol options in the southern Spratlys. Combined with stronger harbors and defenses, it would make Vietnamese positions harder to threaten or blockade and increase the costs of an assault.

Vietnam still faces the difficulty of defending every position against a determined attack by a much larger adversary. Its buildout raises the risks an attacker would face, including the possibility of a wider confrontation. Making coercion or an assault more costly is central to the deterrent value of the expanded network.

Reef damage complicates environmental disputes

Dredging and landfill damage fragile coral ecosystems. Reclamation buries reefs beneath sand and silt, changes the seabed and can harm nearby fisheries. The environmental costs sit alongside the safety and security benefits Hanoi associates with the projects.

Environmental damage has already been part of legal debates over South China Sea activity. Some Philippine officials have considered legal action over ecological harm from island construction. That approach once appeared promising because of the scale of China's dredging earlier in the decade.

Vietnam's large reclamation program complicates a strategy aimed at one country's environmental damage. A Philippine case focused on China's construction could draw accusations of double standards unless Manila also addressed Vietnam's work. The issue may steer claimants toward challenges to unlawful maritime claims rather than cases centered on ecological harm.

An environmental legal strategy remains possible. Its political difficulties now include dealing with reclamation by more than one claimant, while the underlying rule stays the same: creating land does not create new maritime rights.

Vietnam describes shelters, piers and other improvements as support for fishermen and personnel exposed to stronger storms and more aggressive encounters at sea. Those facilities also improve military logistics. Regional responses will continue to reflect both functions, alongside concern about damage to the reefs and fishing grounds.

Permanent facilities are the next focus

Landfill is approaching completion at several features, making permanent construction the likely next phase. More work is expected on piers, protective barriers, air defense positions and communications facilities. Repeated building layouts across the outposts suggest a standard plan for garrisons and storage.

Barque Canada appears set to remain the only new airfield in the near term. At other long features, buildings and depots already occupy the corridors needed for extended runways. The broader network is developing around maritime access, supplies and defenses rather than a new airstrip at every large position.

The Philippines has concentrated on resupply missions and legal and diplomatic efforts rather than a comparable program of large reclamation. Malaysia and Indonesia have remained quiet about Vietnam's expansion, and neither is considered likely to undertake major reclamation soon. More capable Vietnamese outposts could nevertheless encourage neighboring governments to improve their facilities or adjust patrol patterns over time.

ASEAN and China continue discussing a South China Sea code of conduct, but negotiations are held up by issues unrelated to reclamation. There is little indication that the talks will soon settle questions of access or enforcement.

China is increasing patrols near Vietnam's outposts while continuing pressure on Philippine positions. The United States and several partners have also stepped up maritime cooperation and efforts to strengthen the capabilities of Southeast Asian states. Vietnam is building quietly within that evolving security environment.

The resulting network gives Hanoi more places to shelter ships, store supplies, monitor nearby waters and defend its personnel. Its larger islands have become a permanent part of the contest over presence and logistics in the Spratlys, even as the competing legal claims remain unresolved.

What to Know

• All 21 reefs and low tide elevations occupied by Vietnam now include artificial land, following an expansion that accelerated after 2021.
• Early 2025 estimates put Vietnam's reclaimed area above 3,000 acres, roughly 70 percent of China's construction between 2013 and 2017.
• Eight added harbors increased Vietnam's Spratly harbor network from four to 12, supporting longer deployments and local resupply.
• Barque Canada Reef exceeds four kilometers in length and has a runway roughly 8,000 feet long under construction.
• Expanded outposts include helipads, hardened storage, repeated courtyard building layouts, trenches and coastal defenses.
• China has protested Vietnam's construction while directing more visible maritime pressure at Philippine positions.
• Reclamation damages coral ecosystems and complicates possible environmental legal action. It leaves the legal status of maritime features unchanged.
• Permanent facilities are the likely next construction phase, while Vietnam remains at a military disadvantage compared with China.