By Jia Feimao | 2025-10-27

Japan and Taiwan are moving toward regularized joint coast guard drills, which have now occurred twice since the two sides severed diplomatic ties more than five decades ago.

An exercise that occurred in June but was reported only this month makes clear this nascent cooperation.

The Japanese and Taiwanese coast guards carried out a joint maritime rescue exercise in mid-June on the high seas south of Japan's Sakishima Islands, marking their second public drill within a year.

The Yomiuri Shimbun reported the exercise in October, four months after the fact.

"The vessels closed to within visible range, sharing information and adjusting search areas to strengthen on-site cooperation," the newspaper quoted sources as disclosing.

In the June operation, Japan's large helicopter-equipped patrol vessel Mizuho took part alongside Taiwan's Yunlin, and later continued to Southeast Asia for additional training with Malaysia's maritime authorities, the Yomiuri reported.

The disclosure of these activities by Japanese media has sparked optimism in Taipei that Japanese-Taiwanese maritime cooperation could soon become institutionalized.

Reaching visual range signifies direct operational cooperation, Su Tzu-Yun, director of the Division of Defense Strategy and Resources at Taiwan's Institute for National Defense and Security Research, told Focus.

This year's exercise followed the two forces' joint drill in July 2024, when Japan's patrol vessel Sagami and Taiwan's Hsun Hu No. 9 conducted a search-and-rescue operation off the Boso Peninsula near Izu Oshima.

That event in 2024, the first joint training of the two coast guards since Japan severed diplomatic ties with Taiwan in 1972, drew a formal protest from Beijing.

A milestone

Although the publicly available information about Japanese-Taiwanese joint training is still mainly about maritime rescues and does not include combat maneuvers, it still can be considered a major milestone.

Taiwan's coast guard could serve as a platform for both military and diplomatic cooperation, partly compensating for the navy's inability to engage directly with allied forces, said Su.

Although Tokyo officially maintains that the joint drills are not directed at any third party, Japanese media widely interpret them as a response to China's growing maritime expansion.

China Coast Guard (CCG) vessels maintain a near-constant presence around the disputed Senkaku Islands (Diaoyu Islands in China). Japan's official data show that CCG vessels entered the surrounding waters 355 times in 2024, the highest number since records began in 2008, Kyodo News reported.

Before 2018, Chinese patrols occurred roughly 200 days per year, but as the tonnage of CCG vessels has grown, their presence has become virtually continuous -- even in rough weather.

China's attempts to impose unilateral changes on the high seas by force have intensified in recent years, Japan's 2025 Defense White Paper warned in July.

It described them as the "unprecedented and greatest strategic challenge" to Japan's security and the broader international order.

Shared sovereignty threats

Besides Japan, Taiwan and the Philippines must regularly deal with Chinese incursions into their waters.

Taiwan's front-line island of Kinmen likewise has faced frequent Chinese intrusions. From February 2024 to August 2025, CCG vessels transited Kinmen's waters 85 times, averaging 4.4 incursions per month and staying about two hours each time, Taiwan's coast guard says.

The harassment increased after a February 14, 2024, collision. A pursuing Taiwanese coast guard ship accidentally struck a Chinese speedboat engaged in poaching. Two Chinese fishermen died. The CCG then began patrolling the area under the guise of "law enforcement inspections."

"Both Japan's Senkaku Islands and Taiwan's Kinmen Island face sovereignty threats. Only by deepening their cooperation can Taiwan and Japan respond more effectively. They need to 'share intelligence and address common issues between the two countries' agencies,'" Tetsuo Kotani, professor of global studies at Meikai University in Japan, told NHK in July 2024.

Taiwan and Japan signed a memorandum of understanding on maritime search and rescue in 2017, followed by another in 2018 on combating smuggling and illegal immigration. But their first public joint drill since the diplomatic rupture in 1972 did not take place until 2024.

"China is the biggest driving force behind the concrete cooperation between Taiwanese and Japanese coast guard agencies, a development that Beijing likely did not anticipate," Su told Focus.

China claims more than 80% of the South China Sea, even though a court at The Hague threw out that assertion in 2016.

The Philippines, another neighbor enduring maritime disputes with China, faces similar challenges from CCG vessels, Su said.

"Taiwan, Japan and the Philippines are now in the same boat. It is very likely that such joint training between coast guard units could develop from a bilateral relationship into a multilateral system in the future," he said.