Q&A: As South China Sea confrontations ramp up, what’s the risk of open conflict?

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How are gray zone tactics affecting the chance of escalation in the South China Sea?

While the likelihood of direct war remains limited, accelerated militarization and heightened regional tensions alongside gray zone tactics¹ (see table below) — coercive actions that remain below the threshold of armed conflict — have increased the risk of miscalculation in the South China Sea. 

Maritime activity in the South China Sea

1 January 2025 - 27 May 2026

Beijing has mobilized its coast guard (CCG), maritime militias, and fishing fleets to enhance operational control along its “nine-dash line” claims (see map below).² ACLED data show that these vessels have frequently employed water cannons, dangerous maneuvers, barriers, and blockades against Philippine and Vietnamese vessels in the Paracel and Spratly islands and Scarborough Shoal. It has also continued land reclamation activities, including through the construction of artificial islands and dual-use infrastructure on contested maritime features to expand its military and civilian presence and assert its territorial claims, thereby gradually altering the regional status quo. 

While the mobilization of Chinese paramilitary forces has been particularly pronounced in the Spratly Islands, especially within the Philippine Exclusive Economic Zone (EEZ), military buildup — including artificial island construction and naval deployments for military exercises — has been more evident in the Paracel Islands, as reflected in the recent resumption of construction activities at Antelope Reef.³

In other words, confrontations between Beijing and Manila in the Spratly may represent immediate flashpoints, but the island-building campaigns between Beijing and Hanoi pose broader strategic implications for territorial consolidation, military expansion, and maritime governance. The Antelope Reef, the site of Beijing’s latest land reclamation activities, could become the largest military outpost in Paracels and could accommodate a 2.7-kilometer runway alongside expanded port facilities capable of supporting CCG, maritime militia, and possibly naval vessels.⁴ Given its relative proximity to Hainan and the Chinese mainland, the outpost could strengthen Beijing’s surveillance, logistics, and power-projection capabilities, including in the context of a potential Taiwan-related contingency.⁵ China also increased its deployment of research vessels around reefs and atolls located within the Philippine EEZ in the last six months. Similar deployments in Vietnam’s EEZ in 2019 were used to disrupt Hanoi’s oil and gas operations.⁶

Frequent movements of Chinese survey ships equipped with advanced seabed-mapping and underwater-surveillance capabilities — often accompanied by CCG ships — have triggered responses from the Philippines. Research vessel activity was concentrated around Sabina Shoal, Alicia Annie Reef, and Mischief Reef between April and May. Tensions were particularly heightened near Thitu Island, where the Philippines deployed coast guard vessels and aircraft. Beijing claimed that its activities were legitimate and has accused Philippine forces of harassment.⁷

Moreover, the incidents ACLED’s South China Sea Monitor records for the last six months suggest gray zone activities are expanding beyond conventional maritime operations into technological and intelligence domains. This activity includes electronic interference, including communication jamming, as well as espionage and suspected acts of sabotage targeting critical undersea infrastructure.⁸ 

How are claimant states responding?

Regional states, particularly the Philippines and Vietnam, have strengthened deterrence measures to counter Beijing’s actions and reinforce their sovereignty claims. Vietnam has expanded construction activities across 21 features it occupies in the Spratly, with some analysts suggesting that Hanoi is closing the gap with China’s island-building efforts.⁹ These developments could enhance Vietnam’s operational presence while further consolidating its territorial positions and claims. Meanwhile, the Philippines has deepened defense cooperation with its traditional allies while expanding security partnerships with middle powers. 

The 2026 Balikatan exercises involving the Philippines and its partners demonstrate Manila’s deepening alignment with regional security partners in response to mounting pressure from Beijing.¹⁰ Both Vietnam and the Philippines have also supported freedom of navigation in the region, while the US and its regional allies, including Australia and Japan, continue to conduct freedom of navigation operations, joint military exercises, and broader maritime cooperation in the region. 

So far, all sides have largely refrained from the actual use of force and avoided direct confrontation. This restraint has reduced the immediate likelihood of escalation into open conflict. However, the persistent militarization of the South China Sea, coupled with the absence of effective cooperative measures, has increasingly heightened the risk of miscalculation, unintended escalation, and misinterpretation of strategic intent.

How is the Philippines’ South China Sea strategy evolving?

The Philippines’ South China Sea strategy has been shifting over the past few years, and these shifts seem to have gained a newfound relevance amid the transformations in the US’ global role under the second presidency of Donald Trump. The Philippines has expanded its military partnerships beyond its core alliance with the US, with several joint military exercises in the past few years also involving Australia, Japan, Canada, New Zealand, India, and France. It has complemented this move with non-military campaigns designed to increase the pressure on China, including its so-called transparency initiative that has regularly brought journalists to South China Sea hotspots.¹¹ 

Diplomatically, Manila has also sought to reinforce global support for its territorial claims by anchoring them in the 2016 arbitration rejected by Beijing. However, it is still the military component of its strategy that looks likely to alter the regional security landscape fundamentally, showing Manila’s readiness to look beyond Washington.

Despite the Philippines' decades-long “special relationship” with the US and strained relationship with Beijing, China remains among the Philippines’ top trading partners.¹² The Philippines’ crucial position in the US-China rivalry is consequently especially noteworthy to “middle powers” who find it unappealing to leave their interests in the region to depend solely on relations between the two giants. From the Philippine point of view, not having all its eggs in one basket allows it to play a smarter game. As Beijing, playing off a Trumpian theme, seems to toy with a version of the Monroe Doctrine in the Asia Pacific, Manila is signaling it will not accept that the Philippines and broader Southeast Asia be treated as part of China’s regional playground.¹³ 

As a result, Manila seems to consider it only sensible to continue to expand its relationships with third countries, especially with middle powers with interests in the region, while remaining under the US security umbrella for as long as possible (see timeline below). Already, the middle powers are making their mark. The Australian and Canadian navies have engaged in military exercises with their Philippine counterparts.¹⁴ France and India both held their first-ever military drills with the Philippines in the South China Sea in 2025.¹⁵ France also appointed a resident defense attache to Manila in 2024.¹⁶ In March 2026, the Philippines and France signed a status of visiting forces agreement — the Philippines’ first such military pact with a European country.¹⁷ This follows similar agreements with Japan, New Zealand, and Canada, all signed under the present Marcos administration. A similar agreement with the United Kingdom is under negotiation.¹⁸

This Philippine strategy of engaging with more players in the regional waters is not one that pleases Beijing, which routinely criticizes such deployments as “provocations.”¹⁹ Still, it is not these third countries — but the US — that have placed rockets capable of reaching Mainland China on Philippine soil, as underscored by the US’ first-ever test launch of a Tomahawk missile with a Typhon missile system in the Philippines in May 2026 (see map below).²⁰ As such, despite its public expressions of displeasure, Beijing may find itself hoping that Manila’s expanding military relationships will transition, inadvertently or not, to a slow drift away from Washington, even as US Defense Secretary Pete Hegseth instead spoke of “burden-sharing” at the most recent Shangri-La dialogue.²¹

As things stand, none of Manila’s newer partners so far seem willing or capable of matching the sheer largesse that Washington has made available to Manila, with the US most recently earmarking 2.5 billion USD in military aid to the country in 2025.²² Therefore, while Manila’s expanded alliances have attracted attention, if war breaks out tomorrow, the Philippines’ defense will still largely be determined by US military spending.

How does China balance its ambitions for Taiwan with the risk of escalation in the South China Sea?

By China’s public posturing, as underlined most recently in the summit between President Xi Jinping and Trump in May, it is clear that Taiwan remains the most important foreign policy question for China.²³ Therefore, however much attention China pays to the South China Sea, it is worth remembering that Taiwan will always be a factor in Beijing’s calculus for the disputed waters. 

Ultimately, no matter how insistent China is with its nine-dash line claims, it is hard to imagine a scenario where China will allow its interests in the mostly uninhabited islets and rocky features of the disputed waters — despite its indispensability to global navigation and trade, as well as its proven oil reserves — to get in the way of its interests over a nation of over 20 million people. Taiwan is clearly of emotional importance to the Communist Party of China, and even to the national self-image, given the shared history dating back to the founding days of the People’s Republic.

China does not seem hesitant to play a long game in the South China Sea, knowing full well that such entanglements must not get in the way of its plans for Taiwan. Therefore, while the use of gray zone tactics has increased, they appear to be a hard limit for Beijing — at least for now. The Philippines and the US still have an MDT, and the repeated public reassertions of both countries’ defense commitments to each other, therefore, likely play quite a significant role in maintaining the peace. Beijing will likely not want its careful and patient military buildup to suddenly be sucked into the vortex of a war with the US over the defense of Philippine claims over uninhabited islets. 

Still, this game of brinkmanship between China and the Philippines is not without major risks, and it will likely not take more than the unintended loss of life or serious injury to spark a serious risk of conflict, especially with the near-constant American military presence in the Philippines. Filipinos will easily remember that the Philippine-American war of 1899 broke out when a Filipino advancing toward a bridge was summarily shot down by a soldier of the US, which was then the new occupying power that took over from Spain. It would therefore not be unprecedented in Philippine history if war in the South China Sea were to break out in exactly the same fashion — for example, if a vessel that is directed to stop does not stop, and one side fires a lethal shot in any of the contested features.

All the uncertainty in such a scenario — the prospect of all-out war between China on one side and the Philippines and the US on the other — might just be the definitive disincentive to risking any war in the South China Sea, especially for a military with as little active combat experience as the People’s Liberation Army. While the Philippines has been carrying out drills with the US and other partner nations in the South China Sea, China’s drills still seem mostly focused on Taiwan (see map below). This does seem to indicate that if war is to break out, Beijing believes it is far likelier to be over Taiwan than over the South China Sea. That said, the South China Sea will likely be a critical staging ground in that hypothetical war, so even just by dint of geography, the fates of Taiwan and the South China Sea are intertwined.

To what extent can renewed ASEAN-China efforts toward a code of conduct contribute to de-escalation? 

The renewed momentum to negotiate and finalize the COC reflects a shared interest in advancing regional diplomacy and mitigating maritime conflicts. A non-binding COC that avoids politically sensitive issues such as accountability, attribution of violations, and enforcement mechanisms is unlikely to reduce tensions or alter state behavior in the South China Sea. However, renewed negotiations could still improve communication between the contested parties, build trust, improve coordination, and reduce chances of miscalculation.   

Nonetheless, the prospects of concluding a substantive and effective agreement by the end of the 2026 deadline appear slim for three reasons. First, while negotiators have reportedly agreed on roughly 70% of the draft, the most contentious issues — geographical scope, legal status, self-restraint, and the role of other powers outside the region — remain unresolved (see visual below).²⁴ This reflects the persistent legal and strategic divergences between China and several ASEAN claimant states, particularly the Philippines, regarding the interpretation of the COC. The Philippines advocates for a legally binding COC grounded in the principles of the United Nations Convention on the Law of the Sea (UNCLOS), while China favors a flexible, nonbinding framework that minimizes external oversight and preserves strategic ambiguity. China’s insistence on prohibiting joint military exercises with regional partners directly conflicts with the Philippines’ broader deterrence strategy and its security partnerships with countries outside the region.

Second, ASEAN’s institutional structure, which is built on consensus-based decision-making and neutrality, has long posed additional constraints on developing a unified position on the agreement. Diverging threat perceptions and differing levels of economic dependence on China among both claimant and non-claimant states frequently result in diluted or ambiguous language in official agreements.²⁵ Consequently, if the COC is ever finalized, it may lack sufficient political substance to impose reputational or diplomatic costs on coercive behavior or to establish credible mechanisms for accountability and risk management. Such outcomes may inadvertently normalize persistent maritime coercion and further weaken the significance of the South China Sea Arbitration ruling in favor of the Philippines.

Finally, the effectiveness of a COC would remain constrained by the absence of meaningful enforcement mechanisms. China is unlikely to accept arrangements that significantly limit its strategic flexibility or subject its maritime activities to external scrutiny, particularly when the existing regional balance favors its position. At the same time, other claimant states are expected to continue strengthening their deterrence capabilities through expanded maritime operations, military modernization, and closer security cooperation with their partners. These dynamics are likely to sustain a cycle of strategic competition that increases operational friction, deepens mistrust, and raises the risk of miscalculation at sea.

In this context, achieving a COC that simultaneously satisfies China’s strategic preferences while providing adequate assurances and protections for the Philippines and other claimant states appears unlikely within the 2026 timeframe. However, the renewed negotiations remain significant insofar as they reinforce ASEAN’s role as a central regional platform for diplomacy, confidence-building, and norm-setting. Although unlikely to resolve the core disputes, continued dialogue and institutional engagement may still help reduce the risk of unintended escalation in the South China Sea.