The Chinese marine research vessel Kexue, seen here in this undated photo, was first spotted within Japan's exclusive economic zone about 45 miles north of Ishigaki island on April 15, 2026. (Japan Coast Guard)
A Chinese research vessel operating in waters near Japan’s southwestern islands for nearly two weeks left the area early Wednesday, the third such incident in a month, according to Japan’s coast guard.
The Chinese marine research vessel Kexue was first spotted about 45 miles north of Ishigaki island, about 170 miles east of Taiwan, at 12:30 p.m. April 15, according to a coast guard news release that day.
It left the area and sailed westward at 12:22 a.m. Wednesday, according to another release that day.
The Kexue was seen extending wire-like objects from its sides and stern until April 17, but remained in the area for another week and a half, a coast guard spokesman said by phone Wednesday.
“We conducted surveillance and vigilance while it was in Japan’s exclusive economic zone, but we did not confirm the vessel extending any wires after April 17,” he said.
An exclusive economic zone extends some 200 nautical miles from a nation’s coastal baseline, according to the National Oceanic and Atmospheric Administration. A coastal nation has jurisdiction over resources within this zone.
The coast guard continuously radioed Kexue during its stay and stated that “scientific oceanographic research without Japan’s consent is unacceptable,” according to the Wednesday coast guard release.
Kexue belongs to the state-run Chinese Academy of Sciences’ Institute of Oceanology, according to a fact sheet on the institute’s website. It is equipped with deep-sea, seabed and water column exploration systems and an atmospheric detection system.
“We do not clearly know what they were doing,” the spokesman said.
The sighting follows two others in the last month in the Nansei region, which extends from Kyushu to Taiwan.
On March 30, the coast guard began monitoring the Chinese marine research vessel Xiang Yang Hong 22 after it was spotted lowering pipe- and wire-like objects into the sea about 40 miles west-northwest of Uotsuri Island, the largest of the Senkaku chain, the coast guard said at the time.
Japan administers the Senkakus, but China and Taiwan also claim them as their territory.
The vessel sailed north from the area on April 2, the coast guard said in a release that day.
At about 7 a.m. April 18, the Chinese marine research vessel Xiang Yang Hong 18 extended wire-like objects into waters about 65 miles north-northwest of Kubajima in the Senkaku chain, the coast guard said. It sailed west about six hours later.
It is “not abnormal” to spot three Chinese research vessels so close to Japanese islands within a month, the spokesman said. He declined further comment.
Some Japanese government officials may speak to the press only on condition of anonymity.
In October 2023, Japan lodged diplomatic protests with Beijing after a Chinese research vessel was spotted apparently conducting a survey about 80 miles northeast of Taisho Island, another Senkaku island.
Tensions between Japan and China have risen since November, when Japanese Prime Minister Sanae Takaichi during a parliamentary session said Tokyo could use force if Beijing attacks Taiwan. Chinese President Xi Jinping has pledged to unify the democratic island with the mainland, by force if necessary.
