As the Philippines assumes its position as 2026 ASEAN chair, the Indo-Pacific’s maritime security is set to be elevated to the center of its agenda. The issue is a critical one in the wake of growing regional threats. In this respect, one of the Philippines’ key security partners is Japan, which is leading calls for the bolstering of defense cooperation.
The Takaichi administration has reacted quickly to escalating Chinese aggression in the region which threaten its vision of a Free and Open Indo-Pacific (FOIP). China would already be dominant if not for greater regional cooperation.
Like the Philippines, Japanese sovereign territory is under threat. In December, Chinese jets locked on to Japanese aircraft operating in international waters off Okinawa. This was one of the most severe military developments in recent years.
China’s act was unnecessary and endangered the safety of a Japanese fighter conducting routine counter-surveillance near its sovereign territory. It has been reported that China conducted the training exercise without issuing a customary Notice to Airmen (NOTAM).
In response, Washington and Tokyo, the region’s key security guarantors, emphasized that the move poses a serious threat to Indo-Pacific security.
The Philippines is no stranger to aggressive acts by China. In response to the incident, the Department of National Defense issued a statement expressing its “deep concern over China’s actions,” adding that the Philippines “stands in solidarity with like-minded nations like Japan who choose transparency and adherence to international law over intimidation and provocation.”
Beijing has significantly intensified military activity in the contested West Philippine Sea. The same month as the incident off Okinawa, Chinese forces fired several flares towards a Philippine aircraft undertaking a routine surveillance mission in international waters in a clear act of aggression.
It is therefore unsurprising that the frequency of exchanges and joint training exercises among regional militaries has greatly increased. While diplomacy continues to play an important role, strong rhetoric can only go so far.
Beyond unilateral exercises such as Dagat in November, Manila’s growing participation in bilateral and multilateral exercises with like-minded regional partners such as the United States and Japan, illustrated by the trilateral Maritime Cooperative Activity conducted in September, is essential.
Japan’s Minister of Defense Shinjiro Koizumi has described the current security environment as the most severe and complex his nation has faced since World War II. He is focused on strengthening Japan’s defense capabilities as well as deepening coordination with like-minded partners. The government has brought forward revisions to its three key strategic documents, and the defense budget for fiscal year 2026 is expected to reach a record high.
The Philippine government understands the threats posed to regional security and maritime trade. Throughout 2025, Chinese maritime aggression proved unrelenting. A visceral result is that 74 percent of Filipinos now view China as the “greatest threat” to the Philippines and as a direct threat to national sovereignty and territorial integrity.
Manila has therefore rightfully forged strategic ties with not just regional allies but also further afield with partners like the European Union (EU), particularly on the maritime security front.
Closer to home, however, it is Tokyo which has fast become one of Manila’s most important security allies.
A Reciprocal Access Agreement (RAA) between the two long-term allies came into action in September. The pact serves as the legal basis for the militaries of the two nations operating in each other’s sovereign territory, solidifying prospects for even greater cooperation.
The finalization of the RAA has seen analysts highlight its significance in deterring regional aggression. Little over one month after entering effect, the two countries commenced their first military activity under the new agreement, Doshin-Bayanihan 5-25.
This joint exercise between the two countries’ air forces focused on humanitarian and disaster relief assistance, building on Japan’s humanitarian assistance to communities in Cebu affected by the Sept. 30 earthquake.
Crucially, emerging threats are not constrained solely to the sea. As such, the agreement’s elevation of cooperation to other areas including cyber, ground-level (army) and aerial is a welcome development.
The RAA aligns naturally with the Philippines’ own military modernization efforts and marks a positive new juncture in Philippine-Japanese relations at a critical moment. It has opened the door for wider developments, including a potential transfer of retired Japanese patrol aircraft which will help enhance Philippine security and surveillance ability.
Building unilateral capability will always remain a top priority, but in the current geopolitical environment, relationships with like-minded partners such as Japan are likely to prove the most important long-term strategy.
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Joseph Hammond is journalist and former Fulbright Public Policy fellow.