Japan and the Philippines Join Forces to Resist PRC Coercion
Executive Summary:
- Japan and the Philippines are solidifying their bilateral cooperation into a Comprehensive Strategic Partnership aimed at countering Chinese coercion with an eye toward a potential Taiwan Strait contingency. Bilateral action items include defense hardware, intelligence sharing, and maritime delimitation in the waters east of Taiwan by contesting Beijing’s claims through international law.
- The People’s Republic of China (PRC) views the growing partnership as a “quasi-alliance” that threatens its maritime objectives around Taiwan and the Senkaku Islands. It has responded forcefully by launching maritime patrol operations east of Taiwan, sanctioning the Philippine Secretary of National Defense, and issuing diplomatic condemnations of both countries.
- Japan and the Philippines are recalibrating their defense postures due to greater burden-sharing expectations from the Trump administration. Recent statements from Secretary of Defense Pete Hegseth suggest Washington views these efforts favorably and sees the growing alliance as complementary to its Indo-Pacific posture.
Burgeoning security cooperation between Japan and the Philippines, codified in their new Comprehensive Strategic Partnership, poses a new challenge to the People’s Republic of China’s (PRC) irredentist maritime claims. Following years of coercive behavior from Beijing in the East and South China seas, Tokyo and Manila are cooperating to resist further Chinese encroachment on their respective territorial waters. Their partnership will encompass defense hardware, defense intelligence sharing, and maritime delimitation as well as energy and economic cooperation (Prime Minister’s Office of Japan, May 28).
The PRC is worried. A recent authoritative Zhong Sheng (钟声) commentary described this cooperation as “collusion” (勾连) and a “dangerous step towards destabilizing the Asia-Pacific” (祸乱亚太的危险一步) (People’s Daily, June 7). The two countries have a deep-seated mutual interest in resisting the PRC’s maritime expansionism and preventing a Taiwan Strait conflict. Japanese Prime Minister Sanae Takaichi and Philippine President Ferdinand Marcos Jr. also share a willingness to stand up to Beijing. Changing approaches in U.S. foreign policy, which downplay “confrontation” with the PRC and press allies to shoulder a greater defense burden, will provide additional impetus for Tokyo and Manila’s united front against the PRC (White House, December 2025; U.S. Department of Defense [DoD], January 23, May 30).
Setting Maritime Boundaries
Japan and the Philippines have economic reasons for setting maritime boundaries. They are maritime neighbors that have sovereign rights to explore natural resources within their 200-nautical-mile exclusive economic zones under the United Nations Convention on the Law of the Sea (UNCLOS) (United Nations, accessed June 9). Clarifying their respective jurisdictions can prevent disputes about deep-sea mining, fisheries, and energy reserves.
Geopolitical considerations, however, are the driving force behind Tokyo and Manila’s decision to set new maritime boundaries, as the PRC has aggressively pressed its claims in waters administered by Japan and the Philippines since the early 2010s. Neither country has been able to halt the PRC’s advances, and its intensified military coercion of Taiwan has worsened the situation for both Japan and the Philippines. The Chinese military now frequently operates near both the Japan-administered Senkaku Islands and the Philippines’ Batan Islands (Central News Agency, June 4). The Senkaku Islands, also claimed by both Beijing and Taipei, are located about 105 miles northeast of Taiwan, while the Batan Islands lie roughly 120 miles south.
Japan and the Philippines stand a stronger chance of resisting further Chinese encroachment by working together rather than pursuing isolated efforts. By defining maritime boundaries, the two nations intend to use international law to challenge the PRC’s expansionism. The PRC’s Ministry of Foreign Affairs (MFA) responded in kind, stating that the negotiations are “illegal and invalid, and will not affect China’s claims to rights in the waters east of the island of Taiwan or its exercise of its legitimate rights” (非法无效，不会对中方在台湾岛以东海域的权利主张及行使自身合法权利造成任何影响) (Xinhua, May 29). The PRC subsequently deployed its Coast Guard to the waters east of Taiwan on two occasions (Radio France Internationale, June 7). The second deployment included its largest patrol vessel (Liberty Times [LTN], June 7). [1]
Joint Military Operations and Arms Sales
Beyond maritime negotiations, the Japan–Philippines military relationship poses a greater threat to the Chinese Communist Party (CCP). State media made this comparison explicit, writing that “escalating military collusion” (快速升温的军事勾连) between the two countries “has a far more profound and destructive impact on the regional security landscape” (对地区安全格局的破坏性更为深远) (Global Times, June 2). The commentary further characterized the relationship as a “quasi-alliance” (准同盟).
Japan and the Philippines have taken significant steps to deepen this relationship over the past year. In September 2025, a reciprocal access agreement (RAA) intended to boost interoperability and readiness between their respective militaries came into effect (Hankyoreh, September 11, 2025). Facilitated by the RAA, Japan participated in the annual U.S.–Philippines Balikatan military exercise as a full combatant this year for the first time. The United States will also hold bilateral exercises with Japan, Resolute Dragon 26, in late June (Ministry of Defense of Japan, May 22). During Balikatan—which means “shoulder to shoulder” in Tagalog—Japan fired Type 88 anti-ship missiles overseas, also for the first time (LTN, May 7).
The Philippines will benefit materially from this partnership. The Philippine military believes that the Type 88 missile aligns with its Comprehensive Archipelagic Defense Concept, and Japan has already agreed to expedite the transfer of used Abukuma-class destroyer escorts to the Philippine Navy (Philippine News Agency, May 27, May 29). Japan has not exported lethal weapons since World War II, but Prime Minister Takaichi’s cabinet ended those restrictions in April (The Japan Times, April 21). That decision marks an inflection point for Japan, as it adopts a more assertive security posture in the face of PRC aggression.
Aligning With the United States
Both Japan and the Philippines depend on deepening security ties with Washington to enhance security, though the Trump administration’s public pursuit of détente with the PRC—reinforced by the recent summit in Beijing between President Donald Trump and Chinese President Xi Jinping—may complicate that process (Think China, June 5). The Iran war has also strained U.S. military resources, raising questions about Washington’s force projection capabilities in the Indo-Pacific.
Secretary of Defense Pete Hegseth sought to thread this needle at the recent Shangri-La Dialogue in Singapore. He said that U.S.–PRC relations are the best they have been in years but also expressed concern at the PRC’s “historic military buildup” and vowed to maintain a balance of power in Asia to prevent any country from imposing hegemony on the region. Hegseth framed Korea as a model ally, but also praised Japan and the Philippines for their recent defense efforts, while emphasizing that the United States needs allies who are “partners, not protectorates” (DoD, May 30).
PRC media has pivoted from criticizing the United States in the wake of the Trump–Xi summit to targeting its regional allies. In a recent commentary, Fujian Province’s Strait Herald described how MFA spokesperson Guo Jiakun (郭嘉昆) referred to Philippines Secretary of National Defense Gilberto C. Teodoro Jr as a “clown” (小丑) (Strait Herald, June 8). The article criticized Teodoro for “hyp[ing] the so-called ‘China threat’ and brazenly defend[ing] Japan’s new militarism” (渲染所谓“中国威胁”，并公然为日本新型军国主义狡辩) at the Shangri-La Dialogue. The PRC went a step further on June 11 by officially sanctioning Teodoro and his family. Its MFA cited Teodoro’s past statements regarding the PRC as the cause of the sanctions, stating that his speech “harms the legitimate interest of the PRC and destroys bilateral relations between the PRC and the Philippines” (损害中方正当利益，破坏中菲两国关系) (MFA; Reuters, June 11). Official media in PRC ally North Korea has also accused Japan of “opening markets for various instruments of death and transforming into a warmongering nation” (开辟各种杀人装备销路，向战争国家演化) (Sina, June 3).
Conclusion
U.S. signaling for more amicable relations with the PRC has spurred middle powers to reassess their own defense needs, capabilities, and partnerships. In the case of Japan and the Philippines, however, growing bilateral military ties does not come at the expense of U.S. support: At a trilateral maritime dialogue in Manila on June 8, all three countries “reaffirmed their strong opposition to any unilateral attempts to change the status quo” in the South China Sea (Ministry of Foreign Affairs of Japan, June 8). This cooperation should help stabilize the region by enhancing deterrence.
Notes
[1] An analysis of this coast guard activity will appear in the following issue of China Brief.
