Vietnam continues to make modest improvements to its facilities in the Spratly Islands. In cooperation with Simularity, AMTI has reviewed satellite imagery from the last two years to catalog upgrades to Vietnam’s island outposts since the initiative last surveyed them. This exercise underscores Hanoi’s continuing focus on making its bases more resilient to invasion or blockade and strengthening deterrence by ensuring it can strike Chinese facilities.

Upgrades to West Reef and Sin Cowe Island

Of all of Vietnam’s outposts in the Spratlys, West Reef and Sin Cowe Island have seen the most drastic changes over the last two years.

Most of the 70 acres of dry land at West Reef was the product of land reclamation from 2013 to 2016.

In the past two years, West Reef has seen significant new construction, including several coastal defense installations, administrative buildings, concrete pads and bunkers, and a large tower structure presumably for communications or signals intelligence. The northern and southern tips of the island also saw the construction of a tunnel network similar to those on other Vietnamese features, as well as the planting of vegetation.

Sin Cowe Island also saw significant upgrades over the last two years, most notably the construction of an array of defensive installations along the coastline. This work began in 2019 and is concentrated on the roughly 26 acres of reclaimed land built between 2013 and 2016. The reclaimed area on the north side of Sin Cowe, vegetated in images from 2018, was cleared for the construction of new tunnels and coastal fortifications. A November 2020 image shows the area has now begun to be re-vegetated, suggesting that major work has finished.

The upgrades at West Reef and Sin Cowe Island follow established patterns seen at other Vietnamese outposts in the Spratlys. The coastal defense installations—concrete emplacements often connected to a bunker—are ubiquitous at Vietnam’s larger outposts.

Anti-Air and Coastal Defense Capabilities

Three types of emplacements have been built on most Vietnamese bases in the Spratlys. There are oblong pads that appear to be meant for air defense systems. They are often arranged in triangular formations with dedicated bunkers, as seen at Spratly Island, below. But at some of the smallest outposts, like Pearson Reef, they have been attached to helipads to save space. Their age, size, and orientation suggest these are intended for use by older Soviet anti-air systems like the S-125 Pechora-2TM (SA-3 Goa). Several of these oblong concrete pads are also scattered around each island, usually connected to a bunker and facing the coast (see Sand Cay, Namyit, and Southwest Cay below).

Anti-air and artillery emplacements at (clockwise from top-left) Sand Cay, Central Reef, Namyit Island, Spratly Island, Southwest Cay, and Pearson Reef

The second type of platform, pictured at Sand Cay, Central Reef, and Spratly Island above, features a semi-circular concrete pad most likely intended for use by coastal defense systems. These pads almost invariably point outward along the coast and are usually connected to bunkers. The third type of emplacement is the smaller circular pad seen at Sand Cay, Central Reef, and Southwest Cay above. These tend to be oriented inward, with their connected bunker sitting along the coast.

Most of Vietnam’s larger outposts have had these emplacements for many years. AMTI can confirm their presence on Namyit Island since at least 2006. But after reclaiming land to expand its largest features, Vietnam has had to build additional emplacements along the new coastlines. All 10 islets Vietnam controls—those with more than just a couple rocks above water—feature these emplacements.

Vietnam also reportedly has newer, longer-range weapons systems on its outposts. Reuters reported in 2016 that Hanoi had deployed EXTRA artillery rocket systems recently acquired from Israel to five of the Spratlys. The small size of these systems would make them easy to quickly deploy and conceal. They require minimal supporting infrastructure and could be fired from any of the pads identified above, and probably from any other reasonably flat, hard surface. That means they could easily be present at any, or all, of Vietnam’s ten largest islets. As Olli Suorsa has shown, with a range of 150 kilometers (80 nautical miles), Vietnamese EXTRA systems could already be capable of striking all of China’s Spratly bases.  And that is a considerable deterrent capability for Hanoi.

Other Upgrades

Besides West Reef and Sin Cowe Island, several other Vietnamese features have received more modest upgrades in the last two years.

Pearson Reef and Namyit Island both received an additional radome, housing unknown sensing or communications systems, as well as several administrative buildings.

At Spratly Island, Vietnam finished work on a small radome and constructed several new buildings.

Grierson Reef and Central Reef received large administrative buildings.

And Vietnam also expanded two of its pillbox-like facilities on mostly submerged East Reef and Alison Reef. Each received a second structure connected to the first.

Since 2013, Vietnam has upgraded 9 of its 24 reef-based pillboxes and 12 of its 14 isolated “DK1” platforms in the deeper waters to the southwest, as shown in the interactive below.