More Chinese Warships Pass Near Amami-Oshima as Japan Bolsters Defenses

Chinese naval destroyers have passed through a narrow strait near Japan’s Amami-Oshima at least 10 times this year, according to Japanese surveillance records, raising new concerns over maritime security and defense readiness in the country’s southwest.

The strait, located between Amami-Oshima and Yokatejima, connects the East China Sea with the Pacific Ocean. Portions of the waterway are international waters, but the navigable channel is only about seven miles wide and follows a winding route because of surrounding shallow areas. By comparison, the Miyako Strait farther south is more than 150 miles wide.

Japanese authorities recorded no comparable Chinese naval passages through the Amami-Oshima route in 2025, while 15 were recorded in 2024. Local officials say the growing military traffic is forcing communities to consider scenarios once viewed as remote.

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Naruhito Kamada, mayor of Setouchi on Amami-Oshima, said the narrow waterway creates the possibility of accidents involving naval vessels, fishing boats, or sightseeing ships, and that such risks must now be incorporated into emergency planning. Amami-Oshima has a population of roughly 60,000. Local governments are also studying potential evacuation arrangements in the event of a regional crisis.

Japan sends reinforcements

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Retired Japanese naval officers and security researchers say repeated Chinese transits through the area could help Beijing collect information about nearby waters, seabed conditions, and Japanese defense deployments along the First Island Chain.

Japan has responded by steadily expanding its military presence across the southwest. Two Japan Ground Self-Defense Force bases are already operating on Amami-Oshima, with roughly 600 personnel stationed there, including missile units designed to respond to ships and aircraft.

The Japan Maritime Self-Defense Force also maintains a base on the island that is being rebuilt and expanded to accommodate larger vessels and serve as a logistics hub for nearby islands. Tokyo also plans to deploy military radar on Kitadaito Island, southeast of Amami-Oshima, to improve monitoring of maritime and air activity.

Defense officials are simultaneously pushing for larger stockpiles of ammunition, fuel, critical minerals, food, and medical supplies as Japan prepares for the possibility of a prolonged regional conflict or disrupted supply lines.

During an April visit to Iwo Jima, Japanese Defense Minister Shinjirō Koizumi said large stretches of Japan’s Pacific side still lack sufficient defense infrastructure and contain what he described as effective gaps in coverage.

Rising regional tensions

Japan has described the current security environment as among the most serious it has faced since World War II. Its concerns extend beyond China. Tokyo has also pointed to North Korea’s expanding missile capabilities and increased Russian military activity near Japanese waters and airspace, including exercises near the disputed Southern Kuril Islands.

Japan’s southwestern island chain has taken on greater strategic importance because it stretches toward Taiwan and sits along key routes linking the East China Sea to the wider Pacific. In a regional conflict, those islands could play a critical role in surveillance, logistics, missile defense, and access for Japanese and allied forces, making Chinese naval movements through nearby straits especially significant.

At the same time, China’s growing naval activity near Japan’s southwestern islands comes as Beijing expands its broader military reach into the Western Pacific. For Japanese planners, the issue is not only how often Chinese warships pass through the strait, but what they may be learning during those transits.

Record defense spending

Japan’s defense authorities recently submitted a budget request of roughly US$56 billion for the next fiscal year, with major spending planned for missiles, drones, surveillance systems, and other capabilities. Officials say the increase is intended to strengthen deterrence, improve the defense of remote islands, and prepare for a longer conflict rather than a short-duration confrontation.

Lessons from the war in Ukraine have also pushed Japan to reassess stockpiles of ammunition, energy, food, medicine, and other critical supplies. Still, retired Japanese commanders have cautioned that higher spending alone will not immediately solve shortages in personnel, industrial capacity, and long-term logistics.