Analysis: What's behind Japan and the Philippines stepping up defense ties?

In recent times, Japan and the Philippines have been rapidly deepening their defense cooperation, a trend that has sparked growing concerns among regional observers and citizens of the two countries over the potential security risks and rising geopolitical tensions in the Asia-Pacific.

During a meeting between Japanese Prime Minister Sanae Takaichi and Philippine President Ferdinand Romualdez Marcos Jr. on Thursday, the two sides agreed to upgrade bilateral relations, strengthen defense cooperation and launch negotiations on an intelligence-sharing pact.

The two leaders also decided to "commence formal negotiations to delimit the maritime boundary of the exclusive economic zone and the continental shelf between the two countries."

Japan and the Philippines agreed to formally launch negotiations on the General Security of Military Information Agreement, marking a new stage of deeper intelligence integration between the two countries.

Once the agreement takes effect, Japan and the Philippines will be able to share intelligence directly during joint exercises, maritime patrols and emergency responses, without having to route information through the United States. It will also mark the first time Japan has extended such intelligence cooperation to Southeast Asia.

In addition, the Japanese government has finalized its policy to provide military aid to the Philippine military for the fourth consecutive year. Previously, Japan had provided the Philippines with various military equipment, including coastal surveillance radars.

Japan's military aid and sales to the Philippines are expanding rapidly. According to the outcomes of the meeting, the two sides have agreed to accelerate talks on the transfer of Abukuma-class destroyer escort vessels and other defense equipment to Manila.

While both governments described the move as an effort to uphold regional stability and a rules-based order, critics argue that the strengthening alliance reflects a broader strategic agenda aimed at advancing bloc politics in the region.

Closer military ties

Over the recent years, Japan has steadily elevated military and defense ties with the Philippines under the disguise of multilateral security collaboration. The Philippines, for its part, has become one of Tokyo's closest security partners in Southeast Asia.

Since 2012, Japan had long participated in the annual US-Philippines military drills – Balikatan, which means "shoulder-to-shoulder" – as an observer. Earlier this year, it officially joined as a full participant, dispatching large-scale combat forces to the drills. Most notably, Japan conducted its first-ever overseas live-fire test of the Type 88 surface-to-ship missile on Philippine soil, triggering strong public protests among local residents who denounced being turned into a foreign military firing range.

The entry into force of the Reciprocal Access Agreement in 2025 further removed institutional barriers for military interactions. The agreement allows troops from both countries to enter each other's territory for joint military exercises and logistical cooperation. Japan's Self-Defense Forces have since made frequent deployments to the Philippines under various pretexts.

Earlier this year, the two countries upgraded defense cooperation in the name of disaster relief coordination, essentially expanding military interoperability.

In early May, Japanese Defense Minister Shinjiro Koizumi held talks with Philippine Defense Secretary Gilberto Teodoro in Manila, where they agreed to establish a working-level framework to facilitate the transfer of used Japanese military equipment, including Abukuma-class destroyers, to the Philippines.

An editorial published in the Japanese newspaper Tokyo Shimbun on Thursday stated that Japan's strengthening of relations with the Philippines should not focus on military defense, as this act is not conducive to the long-term development of diplomatic relations between the two countries.

Inciting bloc confrontation

The deepening military collusion between Japan and the Philippines can be regarded as a key link in the US-led network of Asia-Pacific alliances, Lu Hao, a research fellow at the Institute of Japanese Studies at the Chinese Academy of Social Sciences, told CMG.

Motivated by a desire to improve the cost-effectiveness of its alliance cooperation, the US is increasingly shifting forward-deployed alliance obligations to its Asia-Pacific allies such as Japan and the Philippines, Lu said.

For Japan, it attaches great importance to the Philippines' role as a geopolitical pivot in the Asia-Pacific and therefore seeks to bind Manila closely to itself in security and even strategic fields, Lu noted.

He said for the Philippines, it aims to court external forces, including the United States, Japan and Australia, to obtain intelligence support, military assistance and maritime patrol services so as to bolster its confidence in geopolitical games. "Such calculations by Japan and the Philippines are clearly marked by strategic speculation."

Responding to Japan and the Philippines announcing the start of talks on the "delimitation of the exclusive economic zone and continental shelf," Chinese Foreign Ministry spokesperson Mao Ning said the move had seriously violated China's maritime rights.

She said the concerned water area is in the east of China's Taiwan island, and according to China's domestic law and international law including UNCLOS (United Nations Convention on the Law of the Sea), China has exclusive economic zone and continental shelf in this area. 

"Japan and the Philippines' so-called maritime delimitation talks constitute a severe violation of China's maritime rights and interests, UNCLOS and other international law and basic norms governing international relations," she said. "China strongly deplores and firmly opposes that and has lodged serious protests with both countries."

"The so-called delimitation talks are completely illegal, null and void, and will have no effect on China's claims to rights in the area east of the Taiwan island or exercise of China's lawful rights," Mao said, urging Japan and the Philippines to immediately stop any violation of China's maritime rights and interests and take concrete actions to uphold regional peace and stability.