Chinese Vessels Escalate Intrusions into Taiwan’s Maritime Borders

The image of “Zhu Hai Yun,” China’s first unmanned aircraft carrier, was presented to the world. Source: Baidu

The Financial Times (FT) reported on the 26th (local time) that there has recently been a noticeable increase in cases of Chinese marine survey vessels intruding within 24 nautical miles (approximately 27.6 miles) near Taiwan. This is interpreted as strengthening China’s surveillance capabilities while securing marine data in preparation for naval warfare.

Based on its independent analysis of data tracking about 80 vessels from satellite data company Spire Global, the FT revealed that there have been nine intrusions into the borders by Chinese vessels since September last year. This is a significant increase compared to only two cases in the past three years and two cases in the three years before. A notable example is the autonomous unmanned drone aircraft carrier “Zhu Hai Yun,” which is affiliated with the People’s Liberation Army of China and sailed along the entire east coast of Taiwan in November last year. Christopher Sharman, director of the China Maritime Studies Institute under the U.S. Naval War College, explained that “the intrusion of the survey vessel is one of the tools in China’s full-scale pressure campaign targeting Taiwan.”

According to the UN Law of the Sea, each country’s territorial waters extend 12 nautical miles (13.8 miles) from the coast. Within this area, vessels or aircraft from other countries cannot pass without permission. Also, a country can claim up to 24 nautical miles from the coast as contiguous zones, through which they can be granted rights and jurisdiction over marine surface and seabed resources. Taiwan has also stipulated that up to 24 nautical miles are its contiguous zone, and if violated, measures such as ship inspections and forced expulsion for crime prevention can be taken. However, China opposes this, arguing that the 24-nautical-mile contiguous zone set by Taiwan does not exist. The FT pointed out that, due to China’s sovereignty claim over Taiwan and its surrounding waters, it is difficult for Taiwan to secure its contiguous zone under international law.

China has frequently utilized vessels operated by the government and military-affiliated research institutes to assert its sovereignty in disputed waters. In particular, marine research vessels can measure water temperature, salinity, and currents and create seabed maps, making them useful for scientific research and securing data in preparation for naval warfare. According to the FT, China has conducted extensive surveys using marine research vessels near Japan and Guam, a U.S. territory, and in the Indian Ocean, which would be critical in underwater warfare during a U.S.-China war. They also sailed around oil exploration sites within the exclusive economic zones of Vietnam and Malaysia in the South China Sea. Director Sharman said, “Where the marine survey vessels go is where Chinese submarines will go in the future,” and “In particular, Zhu Hai Yun helps the Chinese military draw a picture of the submarine environment.”

The FT also reported that while China used to violate waters in the north and southwest of Taiwan mainly, it has recently been focusing more on the eastern strategic waters. Director Sharman said, “Operating in the east of Taiwan will affect not only Taiwan but also anyone approaching from the east of Taiwan.” This implies that there may be difficulties for U.S. forces to intervene in an emergency in Taiwan.