China’s routine patrols east of Taiwan test the island’s strategic depth, experts say

The China Coast Guard (CCG) said it would begin routine law-enforcement patrols east of Taiwan, a move experts say could compress the island’s strategic depth and reshape the jurisdictional order.

Routine patrols and US response

On July 31, the CCG said it would begin routine law-enforcement patrols in waters east of Taiwan and continue strengthening control over the area to safeguard what it described as normal navigation and operational order.

In response to an inquiry from Taiwan’s Central News Agency, the US Department of State said: “The United States remains concerned by Chinese Coast Guard activity east of Taiwan. China’s actions are deeply destabilizing.”

The department also urged “Beijing to cease its pressure against Taiwan and instead engage in meaningful dialogue with Taiwan’s democratically elected authorities.”

The announcement followed China Coast Guard patrols east of Taiwan on June 1, after Japan and the Philippines announced on May 28 that they would hold negotiations on the delimitation of their exclusive economic zones (EEZs). The planned talks involve waters east of Taiwan but exclude both Taiwan and China.

Three days before Beijing announced that the patrols would become routine, the American Institute in Taiwan (AIT) posted a photo on July 28 showing Taiwanese and US Coast Guard vessels operating together signaling US support for Taiwan.

China views self-ruled Taiwan — officially the Republic of China (ROC) — as a breakaway province and has not ruled out the use of force to achieve unification.

Reshaping the jurisdictional order

Wang Hung-jen (王宏仁), a political science professor at National Cheng Kung University, told TCN that CCG operations east of Taiwan reflect Beijing’s efforts to test and alter the jurisdictional order in Taiwan’s surrounding waters.

The mere presence of CCG vessels in Taiwan’s EEZ or on the high seas would not necessarily violate international law, Wang said.

If Beijing were to claim it was enforcing the law in “Chinese jurisdictional waters” and began questioning commercial vessels, requiring them to report their courses, disrupting navigation or conducting inspections, the legal and security implications would change fundamentally, Wang added.

Sun Kuo-hsiang (孫國祥), a professor in the Department of International Affairs and Business at Nanhua University, told TCN that Beijing’s declaration of routine law-enforcement patrols is intended to bring waters east of Taiwan within the scope of its claimed law-enforcement and rights-protection operations.

The objective, Sun said, is not merely to carry out a single incursion but to build a political and legal narrative that China has jurisdiction over the area. 

Impact on Taiwan’s security

If such patrols continue and gradually become normalized, Wang said, Beijing could use legal declarations and enforcement operations at sea to create the impression that it has jurisdiction over the relevant waters, thereby changing the regional order.

Waters east of Taiwan have traditionally been regarded as a relatively safe strategic rear area, Wang said. 

As Chinese maritime activity has gradually expanded east of Taiwan, “this shows that Taiwan’s strategic depth is being compressed,” he said.

Waters east of Taiwan are important not only to the island’s energy supplies and maritime transport but also to US and Japanese force deployments and the broader Indo-Pacific security architecture, Wang added.

Sun expressed a similar view, saying normalized CCG patrols could strain the response capacity of Taiwan’s Coast Guard and Navy, test the island’s eastern strategic depth, threaten shipping and fishing safety off Hualien and Taitung, and extend cross-strait pressure from Taiwan’s west, north and south to its east.

Over the longer term, he said, the operations amount to a maritime form of cognitive warfare — using the language of law enforcement to expand jurisdictional claims and weaken the factual basis for Taiwan’s peaceful administration of surrounding waters.

Salami slicing tactics

Wang said any attempt by China to intercept, inspect or otherwise interfere with commercial vessels would raise the risk of miscalculation and accidental confrontation.

He said Beijing may be employing a "salami-slicing" strategy by first creating precedents through limited actions, then gradually increasing patrol frequency and the number of vessels involved, before ultimately establishing fixed patrol routes and normalized enforcement operations.

Taiwan’s priority, Wang said, is to prevent this normalization from taking hold.

The impact of US responses

Regarding the US response, Wang said Washington has already conveyed political and informational deterrence through public statements and AIT's publication of a photograph showing Taiwanese and US Coast Guard vessels together.

However, Wang said the current deterrent posture remains largely limited to political declarations and messaging and has not developed into a comprehensive framework capable of compelling Beijing to halt such operations.

CCG vessels are therefore likely to continue appearing east of Taiwan, although Beijing may calibrate the intensity of its operations to avoid triggering an immediate crisis, he said.

Wang said Taiwan and the US may not establish a standing joint patrol mechanism, but could strengthen intelligence sharing, joint training and maritime cooperation.

Sun similarly described the US response as a form of political deterrence and the public disclosure of maritime law-enforcement cooperation, rather than a sign of military escalation.

He said future interactions among China, the US and Taiwan could see China maintaining pressure under the banner of law enforcement, Washington increasing public signaling and discreet joint training, and Taiwan maintaining on-site, Coast Guard-led response backed by the military.

The waters of the first island chain are likely to see increasingly frequent, multilayered competition involving coast guards, naval forces and allied vessels, Sun added.

Implications for a potential Trump-Xi summit

Regarding a reported September meeting between US President Donald Trump and Chinese President Xi Jinping, Sun said maritime frictions in the Taiwan Strait and South China Sea would likely add pressure to the agenda, but would not necessarily force the meeting's cancellation.

If the meeting proceeds, Taiwan-related issues, South China Sea disputes and maritime law-enforcement frictions could become bargaining chips before the summit and risk-management issues during it, he said.

Beijing may seek to maintain pressure at sea while avoiding an incident that could undermine the atmosphere of the meeting, Sun said, while Washington is likely to frame developments in both the South China Sea and Taiwan Strait as regional-order issues involving opposition to unilateral changes to the status quo.

Wang said Beijing is unlikely to suspend Coast Guard operations merely to preserve a favorable atmosphere for a summit. Instead, Wang said, it could sustain or even increase maritime pressure before the meeting, using Taiwan and surrounding waters as leverage in negotiations with Washington.

Beijing could seek US concessions on Taiwan-related cooperation in exchange for what it calls “strategic stability,” Wang said. But any such concessions could also be portrayed by China as a US retreat, creating a significant policy challenge for Washington, Wang added.

Taiwan’s response

On Taiwan's response, Wang recommended the government adopt a tiered response mechanism. 

He said Taiwan should avoid overreacting if Chinese vessels merely sail through its exclusive economic zone or operate on the high seas. However, if Beijing begins asserting jurisdiction, interfering with commercial vessels or conducting boardings, the government should gather complete evidence, disclose it publicly and explain the nature of the incidents to the international community.

He said the Coast Guard should continue leading the frontline response, with the military providing backup, to avoid allowing Beijing to portray the incidents as a military standoff.

Sun offered similar recommendations, saying Taiwan should adopt a "calm, transparent, legalistic and internationalized" response at this stage, with the Coast Guard monitoring, gathering evidence and issuing radio warnings on-site in accordance with the law, to prevent China from escalating incidents into a military confrontation.

Sun said Taiwan should make clear in its public messaging that China is using its coast guard to present an expansion of its sovereignty claims as law enforcement. He said Taiwan should continue releasing vessel tracks, imagery and legal positions, and work with like-minded countries including the US, Japan and the Philippines to incorporate waters east of Taiwan into discussions on first-island-chain maritime security, while simultaneously strengthening various surveillance and patrol capabilities in eastern waters.