The presence of three Chinese research vessels in the Indian Ocean elicited heightened attention from India’s maritime surveillance agencies. The ships Shi Yan 6, Shen Hai Yi Hao, and Lan Hai, carrying out scientific or ocean studies, have potential dual-use purposes.

This development points to China’s growing interest in understanding and observing the Indian Ocean, which is a region that plays a central role in India’s security and economic interests.

Shi Yan 6, which is known as China’s first geophysical ocean research ship, is now on its way to Mauritius. While the official statement says that it will carry out marine geological and geophysical surveys, Indian observers suggest that the mission is a part of Beijing’s wider effort to build strong maritime domain awareness.

The ship carries tools like sub-bottom profilers, magnetometers, and multibeam echo sounders. These instruments can create very detailed maps of the seabed can be used for resource searches and submarine movement.

Shen Hai Yi Hao, another Chinese research vessel, entered the Indian Ocean in early November 2025. It was commissioned in 2019 and supports the Jiaolong manned submersible, which can dive deeper than 7000 metres. Although the ship is officially headed to Male in the Maldives, its tasks include collecting deep-sea samples and mapping underwater features. Defence experts believe that ships like this can also assist in studying undersea structures that are important for submarine operations or cable laying routes.

Lan Hai, the third vessel, is already doing survey work in the eastern part of the Indian Ocean, and even though this visit is described as a scientific expedition, Indian maritime watchers feel that the three ships may be working together to study important underwater features from the Bay of Bengal to the Arabian Sea.

This kind of activity fits into a pattern of Chinese research ships working close to major sea routes and island areas across the Indo-Pacific.

India has increased its satellite and naval tracking of foreign research ships that work near its maritime boundary and Exclusive Economic Zone. The Ministry of Defence and the Indian Navy’s Information Management and Analysis Centre are watching all three ships. These kinds of missions often lead to diplomatic caution, leading to denial of port access at Indian locations, as happened in earlier cases with similar Chinese ships.

The timing of these Chinese surveys has gained more importance after the sudden cancellation of a Notice to Airmen linked to a BrahMos missile test near the Andaman and Nicobar Islands. Although officials have not linked the two events, the sequence shows India’s concern about foreign hydrographic work that can support future military or strategic goals.

China stated that its ocean research is for peaceful and scientific reasons. However, analysts see these missions as a part of Beijing’s long-term plan to improve its understanding of the undersea environment, especially in areas that matter for the People’s Liberation Army Navy.

The Indian Ocean, a maritime area dominated by the Indian Navy, is now recording more Chinese scientific visits that blur the line between simple research and naval observation.

With three Chinese ships working at the same time, Indian defence officials are likely to increase maritime domain monitoring and may also work with friendly navies for a wider regional watch. This latest deployment shows how ocean research has become a strategic space where data and mapping work can turn into direct military advantage.

Keywords:
China, Indian Ocean, research vessels, Shi Yan