Responding to a More Coercive Chinese Coast Guard and a Potential PRC Quarantine of Taiwan

Remote Visualization


On May 23 and 24, the People’s Republic of China (PRC) conducted its latest large-scale military exercise (Joint Sword-2024A) along with law enforcement operations around Taiwan, signaling the growing PRC threat of a quarantine or blockade of Taiwan. As part of a range of PRC activities, China exercised “military-police” coordination between the People’s Liberation Army (PLA) and the China Coast Guard (CCG) to surround the main island of Taiwan and Taiwan-controlled outlying islands. The CCG released images of its intended operations around Taiwan’s Dongyin and Wuqiu islands, intruding into the restricted waters of both outlying islands.

PRC media also shared videos of CCG Fleet 2304 conducting law enforcement drills to the east of the main island of Taiwan near Hualien County. The CCG identified and warned a fishing vessel (which appeared to be PRC-flagged), requested the vessel to stop and undergo inspection, and surrounded and boarded the vessel. PRC media also displayed the use of a water cannon, suggesting that the CCG could use such means against intruding vessels.

Growing Risk of PRC Quarantine of Taiwan

The large-scale operations demonstrate one way China could “punish” Taiwan for what Beijing views as Taipei’s “provocation” and “Taiwan independence” activities. These actions build on increased CCG activities against Taiwan since February 2024, when the CCG began more regularly patrolling the waters around Kinmen Island after an unfortunate maritime incident that led to a loss of lives on the PRC side. In mid-May, approximately one week prior to Joint Sword-2024A, Chinese official media stated that this “Kinmen model” of law enforcement inspections “can also be applied to Matsu and Penghu islands, and even the entire Taiwan Strait.”

Indeed, over the years, China has laid out the legal foundation to allow its coast guard to conduct such operations. In 2021, China passed the China Coast Guard Law, which allows the CCG to engage in law enforcement operations in “maritime areas under Chinese jurisdiction” (without defining what those areas are) and to conduct forcible eviction of foreign military vessels that “violate” Chinese domestic law. The law stipulated that China may use all means—including weapons—against foreign organizations or individuals that infringe on Chinese sovereignty, and it can set up provisional maritime warning areas in which the passage of vessels and people could be restricted or prohibited. This May, China passed additional regulations that allow the CCG to detain foreign ships that illegally enter Chinese waters.

The United States, Taiwan, and the International Community Are Ill Prepared to Respond

Despite the growing role the CCG could play in PRC gray zone and military operations, the United States, Taiwan, and close U.S. allies and partners are ill prepared to deal with this challenge. Several factors complicate mounting an effective response.

First, there is a misperception that the CCG is similar to the coast guards of most other countries. Internationally, including in East Asia, most coast guards are civilian-led law enforcement organizations, rather than part of a country’s military, particularly during peacetime. Japan’s coast guard, for example, falls under the Ministry of Land, Infrastructure, Transport, and Tourism and is not allowed to operate as a military force except in the event of hostilities, when it can fall under the authorities of the Ministry of Defense. Similarly, South Korea’s coast guard is part of its Ministry of Maritime Affairs and Fisheries. The Philippines’ coast guard is part of its Department of Transportation and Communications and can be attached to its Department of National Defense during wartime.

The CCG is different and has become increasingly militarized over the years. In 2018, the CCG was moved from under the civilian State Oceanic Administration to under the People’s Armed Police, a paramilitary force that reports to China’s Central Military Commission. China’s 2021 China Coast Guard Law stated that the CCG could execute military operations and take orders from China’s Central Military Commission, a body led by Chinese leader Xi Jinping that has ultimate authority over the military. The law did not specify that this had to be during wartime or a crisis. In other words, the CCG could conduct military operations in peacetime, under the direction of China’s military leadership.

Beijing could take advantage of international perceptions that the coast guard is a nonmilitary, civilian actor to implement a de facto quarantine of Taiwan, where Beijing seeks to impose control over Taiwan by disrupting or cutting off air or maritime traffic to the island. The CCG would be at the frontlines, supported by China’s civilian Maritime Safety Administration (MSA), the PLA, and China’s maritime militia (a force of organized, trained, and armed personnel that supports China’s maritime law enforcement and military operations). China would try to make the case that the CCG activity is a normal law enforcement and domestic operation—and therefore legitimate. Beijing would argue that its actions constitute neither a military blockade nor a declaration of war against Taiwan. This casting of a quarantine as a law enforcement operation, below the threshold for armed conflict, would be meant to deflect and dilute international criticism and pressure.

Second, the PRC could tailor a CCG-led quarantine of Taiwan to try to minimize international involvement and complicate decisionmaking. For example, China would not have to close off the Taiwan Strait to encircle Taiwan. It could selectively isolate certain ports or Taiwan-bound shipping without disrupting maritime traffic as a whole. Doing so would complicate the decisions of the United States and other countries on how to respond—and even whether a response is warranted at all. The United States and many other countries would, on the basis of international law, view any complete closure of the Taiwan strait as blocking an international waterway that is “absolutely essential for global commerce and prosperity.” This would be a direct challenge to “freedoms of navigation, overflight, and other rightful uses of the sea and air.” But a selective or partial PRC quarantine that does not significantly impact international trade in the Taiwan Strait would be more ambiguous and pose challenges to the United States and other Taiwan partners.

China could also engage in selective and periodic enforcement of its quarantine rules. Beijing would not have to force total compliance from shipping companies to achieve its desired effects of punishing Taiwan, creating market disruptions, and demonstrating significant control over the island. Thus, Chinese law enforcement could avoid targeting shipping vessels belonging to the United States or key allies and partners such as Japan to avoid their direct intervention.

Third, the CCG is the largest coast guard force in the world. Taiwan’s coast guard forces, though very capable, are significantly outnumbered and outsized by the CCG. Taiwan also cannot match the ability of the CCG to draw resources from China’s MSA, which has at least three dozen oceangoing vessels as well as hundreds of smaller patrol craft. Taiwan also lacks a large maritime militia force, whereas the PRC maritime militia comprises potentially hundreds or thousands of fishing vessels that can be organized to support Beijing’s maritime claims. Faced with a CCG-led quarantine, Taiwan’s only recourse would be to consider responding with naval forces—a step that could be seen by the international community as escalatory.

Similarly, the United States does not have sufficient forward-deployed coast guard forces in theater to respond in kind. The U.S. Coast Guard’s 14th district has responsibility for a vast area that encompasses much of the western Pacific, including Hawaii, Guam, the Commonwealth of the Northern Mariana Islands, and American Samoa. Just four ships are homeported in Guam, the closest location to Taiwan.

For its part, Japan has one of the larger and best-trained coast guard forces in the region. The Japan Coast Guard (JCG) boasts more than 100 large- and medium-sized patrol vessels, including 17 with embarked helicopters. Around 20 vessels are based in Okinawa alone—the prefecture closest to Taiwan—to enforce Japanese interests in the East China Sea and the waters around the contested Senkaku Islands. 

However, JCG operations are tightly constrained by domestic laws that limit its activities to law enforcement operations in defense of Japan’s territorial waters and exclusive economic zone, and Japan maintains a strict firewall between the JCG and Maritime Self Defense Force. Indeed, information sharing between the two services historically has been poor. Even if the Japanese government wanted to assist Taiwan, the JCG has no legal authority today to respond to a quarantine of Taiwan by escorting foreign ships into or out of Taiwan’s ports, for example.


Given the growing plausibility of a quarantine scenario, Taiwan, the United States, and U.S. allies and partners (especially Japan) should develop more effective tools and strategies for responding.

Taiwan should expand its coast guard to be a more effective counterweight to the CCG. In 2018, Taiwan launched important measures to build up its coast guard by 2027, including building 141 coast guard vessels. President William Lai’s administration, which took office on May 20, should ensure that this program continues with minimal disruption, and it should consider other options to enhance its coast guard forces.

The U.S. government needs to take measures as well. First, Washington should designate China’s coast guard as an arm of the PLA and launch a major diplomatic campaign to persuade allies and partners to do the same. This effort should be aimed at ensuring that China is unable to benefit from international perceptions that the CCG is a nonmilitary organization and to leverage those perceptions to engage in illegal, coercive, and aggressive CCG activities. Washington should state clearly and publicly that a military response to CCG coercion is on the table and legitimate.

Second, the United States should increase its coast guard presence in the region. The U.S. Coast Guard has a sizeable overseas presence, but its Pacific forces cover a vast area of responsibility. A greater concentration of forces in the Western Pacific would provide Washington with increased capacity for training and regional engagement, including with Taiwan—which it could undertake as a law enforcement function under existing policy. A larger U.S. Coast Guard presence would also give the United States more tools for responding to a gray zone contingency involving the CCG. Doing so would require an explicit decision to expand the role of the U.S. Coast Guard as a foreign policy instrument.

Finally, the United States does not have to act alone to deter and respond to a Chinese quarantine operation. Washington should encourage allies and partners to make similar decisions about designating the CCG as an arm of the PLA and authorizing military responses accordingly. Washington should also seek to solidify and increase cooperation with Taiwan’s coast guard and to encourage other allies and partners such as Japan and the Philippines to do the same. It should engage allies and partners in a dialogue on the authorities necessary to respond to PRC coercion below the threshold of military conflict that involves the CCG. Japan, for example, should consider giving its coast guard greater authority to assist Taiwan during a gray zone quarantine, in consultation with Washington. As part of this, the United States and Japan can share best practices on how to respond to CCG and PLA activities and should also conduct joint exercises that explore how to break a quarantine or establish a preventive corridor.

Christopher Johnstone is senior adviser and Japan Chair at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Bonny Lin is a senior fellow for Asian security and director of the China Power Project at CSIS.

Bonny Lin
Director, China Power Project and Senior Fellow, Asian Security