Chinese research vessels loiter near Pacific undersea cables more than any other nation, report finds

CSIS analysis warns the civilian fleet may be collecting data to aid sabotage or submarine operations

By LineZotpaper AI staff

Published26 October 2026

Read Time2 min

Chinese civilian research vessels are spending more time loitering near undersea cables in the Pacific Ocean than the research ships of any other nation, according to a report by the Center for Strategic and International Studies (CSIS), a US-based think tank in Washington, DC.

The analysis, reported by the Indo-Pacific Defense Forum, compared the behaviour of 200 research vessels from 47 nations, including the United States and Russia. It found that Chinese vessels spent a "statistically significant larger share of time" near critical infrastructure and describes the activity as "persistent and disproportionate."

The report suggests China "may be leveraging its research fleet for underwater data collection that may aid... analysis of terrain for sabotage or submarine operations," noting that civilian research vessels provide states with "plausible deniability" for such work.

CSIS cites a ship from the Xiang Yang Hong research fleet which, between July and October 2024, spent time near three undersea cables connecting the United States with Australia, Indonesia, Singapore, Guam and other territories. The vessel moved in a "lawnmower" pattern, which the report says is associated with surveying to create accurate seafloor maps. While the ships are not part of China's navy, the data they collect could serve China in a future conflict, the think tank argues.

CSIS describes these as "gray zone research activities," continuing as Beijing asserts territorial claims in the South China Sea against the Philippines and Vietnam, and maintains its claim over Taiwan, which Beijing considers a breakaway province.

The findings follow last week's report in The Telegraph that recorded 500 incidents of Russian monitoring near undersea cables over the past five years. Iran has also threatened to attack undersea cables in the Strait of Hormuz should conflict with the United States erupt again.

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Analysis

Why This Matters

Undersea cables carry most of the world's intercontinental internet traffic, so damage to them would disrupt global communications and markets.
The activity described is "gray zone": conducted by civilian-looking vessels below the threshold of military confrontation, making it hard to attribute and hard to counter without escalating.
The report adds to growing Western concern over undersea infrastructure security, with Russia and Iran also cited as part of the picture.

Background

Undersea cables carry the bulk of the world's transcontinental data, and protecting them has become a rising focus for Western defence planning in recent years. The Pacific is a particular concern because much of the region's internet traffic moves through submarine cables and strategic competition there has intensified. CSIS's analysis treats civilian research fleets as a blind spot in that picture, since their dual-use data collection is hard to distinguish from ordinary scientific work.

What to Watch

Whether Pacific allies change their posture toward foreign research vessels near cable corridors, and whether any government responds publicly to the report.
Any reaction from Beijing to the findings, and whether the pattern of vessel movements shifts.
Follow-up reporting on cable surveillance, including the Russian incidents documented by The Telegraph and Iran's stated threats in the Strait of Hormuz.

Sources

Chinese research vessels loiter near Pacific undersea cables more than any other nation, report finds · Tom's Hardware

Checked

12 claims in this story checked against 1 source: 10 supported.

Show each claim

SupportedChinese research vessels loiter near Pacific undersea cables more than those of any other nation, the report finds.Latest from Tom's Hardware: “Chinese research vessels loiter near Pacific undersea cables more than any other nation, report finds.”
SupportedThe CSIS analysis warns that China may use its civilian research fleet to collect data that could aid sabotage or submarine operations.Latest from Tom's Hardware: “China "may be leveraging its research fleet for underwater data collection that may aid... analysis of terrain for sabotage or submarine operations."”
SupportedThe report says Chinese civilian research vessels spend more time loitering near Pacific undersea cables than research ships of any other nation.Latest from Tom's Hardware: “China is spending more time loitering near undersea cables in the Pacific Ocean than any other nation, according to a report by the Center for Strategic and International Studies”
SupportedThe analysis compared 200 research vessels from 47 nations, including the United States and Russia.Latest from Tom's Hardware: “The analysis compared the behavior of 200 research vessels from 47 different nations, including the U.S. and Russia”
SupportedThe report found Chinese vessels spent a “statistically significant larger share of time” near critical infrastructure.Latest from Tom's Hardware: “found that Chinese vessels spent a "statistically significant larger share of time" near critical infrastructure.”
SupportedThe report describes the activity as “persistent and disproportionate.”Latest from Tom's Hardware: “It notes that the "persistent and disproportionate activity" means that China”
SupportedThe report says China “may be leveraging its research fleet for underwater data collection that may aid... analysis of terrain for sabotage or submarine operations.”Latest from Tom's Hardware: “China "may be leveraging its research fleet for underwater data collection that may aid... analysis of terrain for sabotage or submarine operations."”
SupportedThe report says civilian research vessels provide states with “plausible deniability” for such work.Latest from Tom's Hardware: “Civilian research vessels provide a unique cover for states looking for "plausible deniability" for their research gathering activities.”
SupportedA ship from the Xiang Yang Hong research fleet spent time near three cables connecting the United States with Australia, Indonesia, Singapore, Guam and other territories between July and October 2024.Latest from Tom's Hardware: “a ship from the Xiang Yang Hong research fleet which, between July and October 2024, spent time near three undersea cables that connected the U.S. with Australia, Indonesia, Singapore, Guam and others.”
Partly supportedThat vessel moved in a “lawnmower” pattern associated with surveying to create accurate seafloor maps.Latest from Tom's Hardware: “The ships move in a "lawnmower" pattern which, it notes, is associated with surveying to create accurate seafloor maps.”
SupportedA Telegraph report last week found 500 incidents of Russian monitoring near undersea cables over the past five years.Latest from Tom's Hardware: “Last week, a report in The Telegraph found 500 incidents of Russian monitoring near undersea cables over the last five years .”
Partly supportedIran has threatened to attack undersea cables in the Strait of Hormuz should conflict with the United States erupt again.Latest from Tom's Hardware: “Iran has threatened to attack undersea cables in the Strait of Hormuz in the event of further assaults by the United States if conflict erupts again.”