Did Japan and the Philippines expand Beijing’s reach in Taiwan’s eastern waters?

Nancy Pelosi’s 2022 visit to Taiwan effectively erased the Taiwan Strait’s longstanding median line. The ongoing Japan-Philippines maritime delimitation talks could have a similar strategic impact in waters east of Taiwan, potentially weakening their defensibility and drawing them into what Beijing treats as its regular patrol zone. When news of the talks first emerged, I assessed that this was the likely trajectory — an assessment that now appears to be reinforced by subsequent Chinese Coast Guard patrols operating in those waters.

The current outcome is, of course, partly a consequence of the Taiwan authorities’ initial response. Faced with Japan-Philippines maritime delimitation talks that clearly touched on Taiwan’s maritime interests, Taiwan’s foreign affairs authorities not only refrained from expressing objection but even voiced “approval”. This, in turn, has been used by Beijing to strengthen its own narrative, allowing it to argue that, in the absence of effective protection by Taipei, it is justified in asserting a law enforcement presence in these waters.

Philippines the pivotal link

Japan and the Philippines announced the start of maritime delimitation talks during Philippine President Ferdinand Marcos Jr’s visit to Japan in May 2026. The target is obviously China. Both countries increasingly feel greater pressure from China and believe they need to join forces to resist it. They have therefore turned their attention to waters east of Taiwan, seeking to incorporate this area into their maritime security cooperation and create space in advance for future joint patrols, joint law enforcement and even military coordination.

The Taiwan authorities’ initial response was also driven by anti-China considerations: they apparently believed that by giving up some of their rights in the eastern waters, they could better align with Japan and the Philippines against China.

In recent years, the struggle between the Philippines and China over islands and reefs in the South China Sea has grown increasingly intense. Although Manila has the support of the US, it often appears to lack sufficient strength. If it can join forces with Japan, its ability to resist China will be enhanced. For Japan, the move is even more significant. If Tokyo wants to build a linkage among the “three seas” — the East China Sea, the Taiwan Strait and the South China Sea — it must bring the Philippines into the picture. This is why relations between the two countries have warmed rapidly over the past two years.

Connecting maritime Japan, Taiwan, Philippines in continuous belt

Yet to jointly resist China, the two countries must also connect their maritime spaces. They need to link the northern Philippines, the Bashi Channel, Taiwan’s eastern waters and Japan’s southwest islands into a single security framework. Japan is now strengthening its military deployment along the southwest islands, from Yonaguni and Ishigaki to Miyako and Okinawa. The entire southwestern direction is being turned into a forward military belt facing the Chinese mainland, Taiwan, and the first island chain. If Taiwan’s eastern waters are further incorporated, in the name of Japan-Philippines delimitation, into a zone of joint management and joint patrols, then Japan’s southwest islands, Taiwan’s eastern offshore waters and the northern Philippines will be connected into one continuous strategic belt.

This is the strategic background behind Japan and the Philippines’ push for maritime delimitation talks.

Manila’s calculation, and especially Tokyo’s, is not hard to understand. If a military conflict breaks out between China and Japan in the future, Japan would naturally hope that the war is confined to the southwest islands, the waters around Taiwan and the forward edge of the first island chain, rather than spreading to the Japanese mainland. If Taiwan’s eastern waters become a space for Japan-Philippines security cooperation, Japan will gain an additional strategic buffer and another entry point for pulling Taiwan further into its security system. Seen from this angle, the so-called Japan-Philippines delimitation is, in essence, an attempt to securitise Taiwan’s eastern waters and push Taiwan further to the front line.

Giving China a chance to counteract

What is most baffling is the reaction of the Taiwan authorities. The maritime zones of Japan and the Philippines are not contiguous; Taiwan lies between them. Therefore, if maritime boundaries are to be delimited, Japan and the Philippines should negotiate separately with Taiwan, or, within the legal framework of one China, with Beijing.

Japan and the Philippines are, of course, fully aware of this reality. Yet they have bypassed Taiwan, and the implication behind this is that they do not recognise Taiwan’s sovereignty. In other words, although both countries formally follow their own versions of a one China policy, through these delimitation talks they are deliberately avoiding the question of Taiwan’s sovereignty and treating Taiwan’s eastern waters as a grey zone that can be handled by Japan and the Philippines on their own, bypassing both Taipei and Beijing. Embedded in this approach is, in effect, the logic of “Taiwan’s status being undetermined”.

Since the Lai Ching-te government came to power, its biggest problem has been that it approaches everything through the ideology of resisting China. It believes that as long as Taiwan stands with the democratic camp, Taiwan will be safer; as long as Taiwan moves closer to Japan, the Philippines and the US, the mainland will be more deterred. But reality often moves in the opposite direction.

Every time Taiwan takes the initiative to push itself into an external security system, the mainland seizes the opportunity to move one step further forward. This was the case after Pelosi’s visit to Taiwan, and it is the case again with Japan and the Philippines announcing maritime delimitation talks. External forces do not necessarily bring Taiwan security. Sometimes they bring even greater danger.

Redrawing lines but losing ground?

As for the Japan-Philippines maritime delimitation talks themselves, they take the area most sensitive to third-party interests and turn it into a bilateral arrangement. Whatever their considerations may be, such delimitation has no real basis in international law; politically, it is illegitimate, and strategically, it is dangerous.

China is now using coast guard law enforcement patrols in waters east of Taiwan to declare its sovereignty in this area. Even if the issue eventually enters an international legal dispute process, Japan and the Philippines may not necessarily have the stronger legal position.

In the maritime contest that follows, what they would originally have faced in this area was merely Taiwan’s coast guard. Now they will mainly face the Chinese mainland’s coast guard. Given the relative strength of the Chinese coast guard against Japan and the Philippines respectively, their chances of success are even smaller, and their hidden intentions will be harder to achieve. Seen in this light, they may be said to have failed in their scheme and hurt themselves in the process. They have turned themselves into losers.

Taiwan could suffer the most

Taiwan, without doubt, is the biggest loser. The most serious consequence of this Japan-Philippines move for Taiwan is that the nature of its eastern waters is changing. In the past, Taiwan’s pressure from the mainland was mainly concentrated to its west, north, and southwest. Its eastern waters were regarded as a relatively safe rear area — important for preserving Taiwan’s forces, receiving external support and maintaining strategic depth. But once mainland coast guard, maritime safety and other law enforcement forces begin to enter regularly, the eastern waters will no longer be Taiwan’s safe rear. They will become another front line.

This is the cruelty of realpolitik. Japan and the Philippines may not necessarily gain any real benefit from this move, but Taiwan alone is left in the most awkward position. If Taiwan protests against Japan and the Philippines, it damages the so-called anti-China cooperation. If it does not protest, it effectively accepts that others can arrange its waters. If it protests against the mainland, it cannot stop mainland law enforcement. If it does not protest against the mainland, it will be accused at home of weakness.

Therefore, from whichever angle one looks at it, the Japan-Philippines maritime delimitation talks have not made Taiwan safer. Instead, they have turned Taiwan’s eastern waters into a new disputed zone, and Taiwan may well lose the status of these waters as a safe rear area. This is not a diplomatic victory, nor an anti-China strategic arrangement. It is a real strategic setback.

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