South Korea raises concerns over China's 'No-Sail Zone' in Yellow Sea

South Korea has formally expressed concerns to China over the recent establishment of a “no-sail zone” in a jointly administered area of the Yellow Sea, Seoul’s foreign ministry announced Saturday.

The AFP cited a report by Newsweek on Wednesday which said, the ministry acknowledged that China had restricted vessel access to parts of the Yellow Sea, located between the Chinese mainland and the Korean Peninsula through May 27.

The restricted area falls within the Provisional Measures Zone (PMZ), where the exclusive economic zones (EEZs) of both countries overlap.

While China’s Maritime Safety Administration (MSA) did not publicly state the reason for the restriction, South Korean media, referencing the Korea Hydrographic and Oceanographic Agency, reported it was likely related to military training.

Although both nations are permitted to conduct military exercises in the PMZ, Seoul criticized the move, stating that “China’s establishment of a no-sail zone within the PMZ that excessively restricts freedom of navigation raises concerns.” The ministry confirmed that these concerns had been communicated to Beijing through diplomatic channels.

Additionally, the South Korean government is working with other agencies, including the Ministry of National Defense, to evaluate whether China’s actions align with international maritime law .

Newsweek also reported that China has erected three structures in the area, which it describes as “aquaculture facilities.” However, some South Korean media outlets have speculated that these developments may represent “grey zone” tactics—deliberately ambiguous actions that could be aimed at expanding Chinese control over disputed maritime areas.