The Japan coast guard warns Chinese coast guard vessels away from the Senkaku Islands in April 2024. (Ishigaki city)

Chinese coast guard vessels sailed near the Senkaku Islands 357 times last year, setting a record for the fourth year in a row amid increased tension between Beijing and Tokyo.

In 2024, China’s coast guard was spotted 355 times in the contiguous zone around the uninhabited island group, which is administered by Japan, a spokeswoman for Japan’s coast guard said by phone Monday. That year in turn broke 2023’s record of 352 sightings.

The contiguous zone is a 24-mile-wide band beyond the 12-mile territorial limit. Countries may exercise limited control in their contiguous zones, according to the United Nations.

The Senkakus, also claimed by China and Taiwan, include five islets and three reefs 105 miles east of Taiwan and 254 miles west of Okinawa.

“The situation surrounding the Senkaku Islands is becoming increasingly severe, and the situation remains unpredictable,” Seishiro Sakamoto, commander of Japan’s 11th Regional Coast Guard, said in a statement the spokeswoman emailed Monday.

“We will continue to conduct surveillance and vigilance activities with a high sense of urgency so as not to miss even the slightest change and will take all possible measures to protect our territorial waters,” Sakamoto said.

China refers to the islands as Diaoyu and maintains that its activities in the adjacent waters are “legitimate and lawful,” then-Foreign Ministry spokesman Lijian Zhao told reporters in July 2022.

“The Japanese side has no right to point fingers over these activities,” he said.

Last year, the Chinese coast guard sailed 27 times into territorial waters around the Senkakus, most recently on Dec. 10, the Japanese coast guard spokeswoman said. On eight instances, the Chinese ships chased Japanese fishing vessels past the territorial limit.

China’s coast guard entered the Senkakus’ territorial waters 39 times in 2024, she said. The record is 52 times in 2013, according to the coast guard.

China also set a record in 2024 and 2025 for consecutive days sailing within the Senkakus’ contiguous zone. Vessels were spotted there for 335 days between Nov. 19, 2024, and Oct. 19, according to the spokeswoman.

The previous record was 215 days between Dec. 22, 2023, and July 23, 2024, according to the coast guard.

The area is believed to contain oil reserves and other resources, fueling Chinese challenges to Japan’s claim over the islands since the 1970s, according to Japan’s Foreign Affairs Ministry.

Tensions between the two countries escalated when Prime Minister Sanae Takaichi during a November parliamentary session warned that Japan could use military force if China attacks Taiwan. Chinese President Xi Jinping has vowed to unify the self-governing island with the mainland, by force if necessary.

The Pentagon has identified China as an aggressive presence in the East and South China seas and a global “pacing challenge” in its 2022 National Defense Strategy.

The 2025 National Security Strategy includes a focus on “competing with China economically and militarily in the Indo-Pacific region,” by prioritizing acquiring weapons such as long-range manned and un-manned aircraft.

Some Japanese government officials speak to the press only on condition of anonymity.