Why the Philippines and Japan are preparing for a Taiwan contingency

During Philippine President Ferdinand Marcos Jr’s state visit to Japan on 26-28 May, Manila and Tokyo emphasised boosting the bilateral defence partnership amid China’s coercive activities in the first island chain, which includes Japan, Taiwan and the Philippines. Marcos Jr and Japanese Prime Minister Takaichi Sanae agreed to elevate the partnership to a comprehensive strategic partnership, reflecting the deepening of interests between the two Indo-Pacific nations.

Closer coordination, common wariness of China

In a landmark development, both leaders announced the commencement of negotiations for the General Security of Military Information Agreement (GSOMIA), an institutional framework to manage and streamline the sharing of sensitive military data for critical operations, thereby improving joint preparedness and contingency planning coordination. Such an agreement could only have been forged with a greater sense of trust between the two countries. The two leaders also agreed to expedite the transfer of Japan’s Abukuma-class destroyer escorts to the Philippines, marking Tokyo’s first export of lethal defence assets to the Southeast Asian nation. 

Both leaders also said they would begin formal talks to delimit the maritime boundary of the exclusive economic zone and the continental shelf between the two countries “in accordance with international law”. Given that the ​maritime area to be negotiated overlaps with Taiwan’s EEZ off its eastern coast, Taipei’s foreign ministry urged both nations to consider its sovereign rights. On the other hand, China, which views Taiwan as its own territory, condemned the plan and sent its coast guard vessels off Taiwan’s east coast as a response.  

However, to better understand the trajectory of contemporary Philippines-Japan security ties, it is necessary to contextualise the internal and external factors shaping decision-making in both countries.

Ratcheting up of Philippines-Japan security relationship

There has been a significant deepening and broadening of Philippines-Japan security cooperation in the last three years, largely due to Tokyo’s reinvigorated perception of regional geopolitics set out in the 2022 National Security Strategy.

With the vision of Japan playing a larger role as a security provider and partner in the Indo-Pacific, Japan established the Overseas Security Assistance (OSA), designed to bolster the deterrence capabilities of like-minded partners in the region. As the first recipient of the OSA, the Philippines received coastal surveillance radar systems and rigid-hulled inflatable boats from Japan.

Another milestone was reached with the signing of the Reciprocal Access Agreement (RAA) in July 2024, which streamlined military-to-military collaborations between the Armed Forces of the Philippines (AFP) and the Japanese Self-Defense Forces (JSDF). 

While Japan’s security assistance has been portrayed as modest and measured, Tokyo has recently reoriented this approach, seeking to deepen the security dimension of the Free and Open Indo-Pacific (FOIP) forged under the Shinzo Abe government in 2016. To that end, the Takaichi administration more than doubled the OSA’s 2026 budget allocation to US$116 million, up from US$54 million the previous year. On 21 April, the Takaichi cabinet also announced its decision to remove Japan’s traditional ban on the export of a wider range of defence equipment with lethal capabilities, including fighter jets, frigates and destroyers. 

Japan’s defence equipment transfer a boost to the Philippines

In this context, the transfer of the Abukuma-class ships to the Philippines becomes even more significant as it would be a notable step forward in Japan’s security-related exports to the Philippines, which have traditionally focused on assets for the civilian-oriented Philippine Coast Guard (PCG). 

To deepen industrial base collaboration, Japan and the Philippines are also looking to establish a working group to oversee the long-term maintenance and management of the ships. Once finalised, the transfer of warships will be a pivotal stepping stone toward greater arms trade between the two nations. The Philippines has also shown interest in Japan’s Type 88 surface-to-ship missile system and its Type 10 tank. To maximise this potential, Manila may tap on the US$500 million in Foreign Military Financing provided by Washington to support the modernisation of the AFP. 

Consequently, since the ratification of the RAA in December 2024, the militaries of both countries have enhanced interoperability and cooperation. One of the most significant operational milestones was the first-ever participation of Japanese combat troops in the 2026 Balikatan exercise between the Philippines and the US, held from April to May. 

The Philippines now has intelligence-sharing agreements with both the US and Japan, while the US also has one with Japan. This set of linkages creates the necessary conditions for all three countries to enhance trilateral coordination for information sharing. Doing so would significantly supplement the trilateral arrangement’s existing efforts to improve interoperability at sea through maritime cooperative activities. 

However, these developments have drawn criticism from China. For instance, it labels Tokyo’s stronger defence posture as a reinvention of Imperial Japan’s legacy during the Second World War. Consequently, this narrative was shut down by Koizumi in his discussion at the Shangri-La Dialogue in Singapore on 31 May. Accordingly, the Japanese defence minister rejected China’s erroneous “new militarism” discourse by stating: “Every country must be able to choose its future by its own will.”

Concerns about US commitment 

During Chinese President Xi Jinping’s summit with US President Trump in May 2026, the former warned that Taiwan was the most sensitive and important issue in Sino-American relations. Additionally, Xi noted that this must not be mishandled to preserve relations between the two powers. This meant that China would not tolerate any attempt by the US to support Taiwan’s independence or improve Taiwan’s capabilities to defend itself. This came against the backdrop of the delays in Washington’s arms sales to Taiwan to ensure the US military has enough munitions for its war against Iran. 

Moreover, after meeting Xi, Trump said he was “not looking to have somebody go independent”. To be fair, however, no US President has ever explicitly stated that Taiwan should be independent. However, he added that he wanted all sides to “cool down”, especially since he was not keen on sending US forces 9,500 miles to fight a war. Furthermore, he also suggested that Washington can use arms sales to Taiwan as a bargaining chip with China. 

Fears of being caught in between or being marginalised

These statements do not necessarily inspire confidence in US security commitments to Taiwan. Indeed, given its involvement in conflicts across multiple regions, from Europe to the Middle East, the US may find it difficult to mount an effective military intervention should China invade Taiwan.

Nevertheless, while such statements from Trump should be taken with a grain of salt, given the unlikeliness for the US to willingly give up its strategic position in the Western Pacific to China, concerns have become more prominent among Taiwan’s immediate neighbours, Japan and the Philippines — both of which have clearly emphasised that a Chinese invasion of the island nation would automatically draw both countries into the conflict.

For instance, in November 2025, in her remarks to the Japanese Diet, Takaichi stated that a Chinese attack on Taiwan might threaten Japanese security and constitute a survival-threatening situation under Japan’s security laws. Moreover, Marcos Jr has repeatedly stated how Taiwan’s security is deeply interconnected with the Philippines. 

For Japan, another pressing issue is Trump’s repeated references to the “G2” model between the US and China. The G2 is a Cold War-era concept that characterised the international system into two spheres of influence between the US and the Soviet Union. By repeating this term, the US intends to view its relations with China in the same light. This is problematic for Japan, which seeks to carve its own pillar of influence in the emerging international system. 

Moreover, the G2 concept strips away the dynamic, multipolar character of the emerging international political landscape, thereby marginalising the important roles played by other key powers, including Japan and India, particularly in the Indo-Pacific. In this regard, Japan has endeavoured to take on a more prominent role in Indo-Pacific geopolitics through its partnership with key like-minded nations, such as the Philippines, and looks set to continue to do so amid geopolitical uncertainties. 

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