On April 1, a spokesperson for the Eastern Theater Command of China’s People’s Liberation Army (PLA) announced that the command had organized a joint military exercise around Taiwan, mobilizing land, sea, air, and rocket forces for integrated operations. It is worth noting that the scale of forces involved in this most recent exercise around Taiwan surpassed that of previous joint combat readiness patrols conducted over the past few years, with additional elements from the PLA Rocket Force and China Coast Guard. Although the exercise was not given the name “Joint Sword,” which has been specifically associated with joint operations drills around Taiwan since 2023, it did encompass cross-service training activities in terms of both scale and intensity.
On April 2, Shi Yi, spokesperson for the Eastern Theater Command, announced that the PLA Eastern Theater Command had carried out the “Strait Thunder 2025A” exercise in the central and southern areas of the Taiwan Strait.
A comprehensive analysis of the two-day military exercise conducted by the PLA reveals a three-phase operational plan that the PLA is likely to adopt for a campaign against Taiwan. Phase one involves joint combat readiness patrols, such as the one conducted in March, marking the stage for troop assembly. Phase two takes a step forward to operations, as demonstrated in the Joint Sword series of exercises, focusing on strikes against sea and land targets and achieving overall battlefield dominance. Finally, phase three involves maneuvers that simulate expelling, intercepting, and detaining ships bound for or departing Taiwan, as demonstrated in the inaugural Strait Thunder exercise.
This sequence highlights the strategic steps behind the PLA’s exercises, along with the underlying tactical considerations and objectives of its training activities.
Testing the United States’ Resolve
Although the Strait Thunder exercise targeted Taiwan, it was also intended as a signal to the United States. Notably, when the exercises were launched, U.S. Secretary of Defense Pete Hegseth had just concluded a meeting and dialogue in Tokyo with Japan’s Minister of Defense Gen Nakatani. During the meeting, the two leaders emphasized the importance of maintaining peace and stability in the Taiwan Strait and strengthening cooperation with partners in the Indo-Pacific region. Shortly after the meeting between the U.S. and Japanese defense chiefs, China launched its new large-scale military exercise around Taiwan.
In addition to the anti-Taiwan independence narratives emphasized by Chinese media, the exercise carried the strategic implication of testing the United States’ limits regarding the Taiwan Strait.
While the Russia-Ukraine War remains a primary focus for U.S. President Donald Trump, U.S. defense memoranda revealed by the media have repeatedly highlighted the need to counter China. This raises the question of what stance the U.S. might take if the security of the Taiwan Strait is jeopardized. Beijing surely wants to understand the Trump administration’s strategic limits ahead of any potential meeting between Xi Jinping and Trump. Testing those limits may have been the diplomatic calculation behind this military exercise.
Particularly, amid significant personnel changes within the U.S. Department of Defense (DOD) following Trump’s inauguration, China may perceive a temporary gap in U.S. military readiness. It does not mean that the DOD lacks plans to address the situation, but the adjustments involving high-ranking officers and Pentagon’s subordinate organizations may lead to delays in policy implementation and decision-making. Taiwan should remain vigilant against the possibility that China might choose to take action during this critical juncture.
Dissecting the Strait Thunder 2025A Exercise
With that context in mind, what exactly did the Strait Thunder 2025A exercise involve?
In contrast to the Joint Sword 2024B drill, which was characterized by rapid progression and a swift conclusion, like a pop-up event, this exercise showcased a notable difference: Strait Thunder 2025A demonstrated phase-specific features of a potential campaign against Taiwan. Moreover, it showed a significant increase in troop deployment.
Over the course of the 33-hour drill, the drills included not only firepower strikes but also, for the first time, “phase two” operations mentioned earlier, such as controlling and blockading maritime vessels entering and leaving Taiwan, along with conducting onboard inspections. Such maneuvers were unprecedented in the Taiwan Strait.
Notably, Beijing assigned this task to the China Coast Guard. The primary concern is that the China Coast Guard, often considered a judicial agency due to its maritime law enforcement duties, is better qualified to enforce the blockade and control of vessels in the waters surrounding Taiwan. This approach circumvents limitations associated with the term “war,” offering China a legal warfare strategy to address the Taiwan Strait issue. Additionally, foregrounding the China Coast Guard symbolizes Beijing’s assertion of judicial jurisdiction and enforcement authority over Taiwan, while also drawing international attention to its so-called One China principle.
It is worth noting that, according to disclosed information, the areas occupied by the PLA’s Shandong aircraft carrier strike group during the Strait Thunder 2025A exercise are strategically significant, threatening Taiwan and Ryukyu Islands to the north while facing the Philippines to the south. However, during the exercise, the Eastern Theater Command spokesperson did not mention the presence of the aircraft carrier Shandong in the West Pacific Ocean, focusing instead on the joint blockade efforts by naval and coast guard forces in the central and southern areas of the Taiwan Strait. The omission of the aircraft carrier and other PLA vessels elsewhere in the briefing on the exercises suggests that Strait Thunder was exclusively concentrated on blockade actions in the central and southern Taiwan Strait, without involving other forces.
The term “joint” in the designation of the PLA’s military exercises refers to cross-branch joint operations, representing a comprehensive integration of multiple sub-plans. Therefore, if future editions of the Strait Thunder series continue to be carried out solely within specific areas, without demonstrating an integration of itemized plans, it could suggest that Strait Thunder is merely a subplan within the broader series of Joint Sword exercises, with the former’s primary mission being the blockade of the Taiwan Strait.
Although Strait Thunder 2025A involved long-range live-fire training activities, the focus was on precision strikes against simulated targets, indicating that its purpose was not to carry out actual blockades and strikes in the exercise areas but rather to simulate the process of live-fire drills. With precision strikes as a key focus, the intensity level of the Strait Thunder drill is higher than that of the joint combat readiness patrols but likely below that of the Joint Sword series.
Strait Thunder is likely a code name for a training subject within a specific joint operations maneuver, rather than the designation for the entire action. In this practice drill, China Coast Guard vessels were responsible for establishing blockades for Taiwan and cargo ships entering or leaving the Taiwan Strait. The navy and air force managed U.S. military aircraft or vessels approaching the exercise areas.
Conclusion
The Chinese military exercise was not merely a reaction to Taiwan President William Lai’s recent “17-point statement” outlining the government’s actions to counter China’s attempts to infiltrate and annex Taiwan. As early as February, there were already signs of PLA vessels operating in the West Pacific, South Pacific, and Northern Indian Oceans. These vessels were conducting anti-access/area denial (A2/AD) and counter-intervention exercises. The PLA’s objective is to block potential routes that the U.S. Fifth Fleet might use to reach the Taiwan Strait to assist Taiwan. These routes include those originating from Guam in the West Pacific Ocean, Australia in the South Pacific Ocean, and bases in the Indian Ocean.
In contrast to the Joint Sword 2024B, which began and ended rapidly, the Strait Thunder 2025A exercise showcased distinctive characteristics of a specific phase of a potential campaign against Taiwan, a clear temporal progression, and a notable increase in the number of forces involved. The main training subjects included firepower strikes and, for the first time, operations specific to the second phase of a potential campaign against Taiwan, involving containing and blockading maritime vessels entering and exiting Taiwan and even conducting boarding inspections – the first drill of its kind in the Taiwan Strait. The China Coast Guard was responsible for this task, indicating Taiwan must also incorporate its coast guard into the country’s defense forces to meet this type of threat.
PLA military exercises are categorized into various levels based on their scale and objectives. Ever since then-U.S. House Speaker Nancy Pelosi’s visit to Taiwan in 2022, the PLA has been saber-rattling against Taiwan, taking actions ranging from test-firing missiles that flew over Taiwan to conducting increasingly frequent joint combat readiness patrols. These moves represent China’s responses to relevant international events and may evolve with changes in the global situation, likely to adopt new names and adaptations.
In analyzing the PLA’s future actions, Taiwan must make a comprehensive assessment, taking into account the breadth of its training subjects as well as their duration and sequence. More importantly, evaluating the PLA’s various actions requires adopting the perspective of interconnected strategies, rather than viewing them as merely isolated events. All of these points require further observation in future studies of the PLA.