Lessons from 335 Days of Chinese Vessels near the Senkaku Islands

China’s 335-day run of coast guard and other government vessels operating in the contiguous zone around the Senkaku Islands, till they withdrew in October, represents a structural shift in maritime coercion. Japan’s coast guard noted the departure and suggested that the weather was a factor in Chinese vessels pulling back; however, the scale and duration of their presence beforehand had already altered routines and risk calculations in Tokyo and among its partners. This prolonged streak far surpasses the earlier record of 215 consecutive days from December 2023 to July 2024, signalling a notable escalation in Chinese maritime activity.

The record for the total number of days of confirmed navigation by China Coast Guard (CCG) vessels stands at 336 days in the contiguous zone surrounding the Senkaku Islands in 2022. In fact, the situation escalated in December 2022, when an intrusion into Japan’s territorial sea lasted over 72 hours, the most extended duration ever recorded. Tokyo views these actions as unilateral attempts by China to alter the status quo by force, constituting clear violations of international law.

Chinese maritime activity around the islands has systematically intensified in recent decades.

Japan maintains that the Senkaku Islands are an inherent and indisputable part of its territory, both historically and under international law, and that they remain under its valid and effective control. Hence, there exists no sovereignty dispute to resolve. The islands were lawfully incorporated into Japanese territory in 1895. Until the 1970s, when the discovery of potential oil reserves in the East China Sea drew renewed interest, China raised no objections to Japan’s sovereignty and has never explained this long silence.

Chinese maritime activity around the islands has systematically intensified in recent decades. The first recorded intrusion by Chinese Marine Surveillance vessels into Japan’s territorial sea occurred in 2008. In 2022 alone, Japan documented 28 such incursions by China Coast Guard vessels, following 34 in 2021 and 24 in 2020. Since May 2020, these vessels have repeatedly entered Japanese territorial waters near the Senkaku and have frequently attempted to approach Japanese fishing boats operating near the island. In June 2025, a Chinese aircraft carrier group - the Liaoning - entered Japan’s exclusive economic zone (EEZ) for the first time, raising alarm in Tokyo over China’s expanding maritime presence. The Liaoning was accompanied by two missile destroyers and a supply vessel and entered the EEZ about 300 km southwest of Minamitori, Japan’s easternmost island, and home to vast seabed deposits of rare metals. Though uninhabited, Minamitori hosts meteorological, self-defence, and coast guard personnel.

During the long streak observed in 2022, Japan reported several notable activities, including Chinese naval survey vessels operating within its territorial waters south of Yakushima; coordinated transits by Chinese and Russian naval vessels in waters surrounding Japan; joint flights by both countries’ strategic bombers; and continued incursions by Chinese vessels into the contiguous zone near the Senkaku Islands.

Repeated, near-daily transits within the contiguous zone erode Tokyo’s ability to treat such movements as exceptional; they become part of the background operational environment that Japanese patrols must continually contend with,

Operationally, the rising frequency and duration of Chinese vessels in Japan’s contiguous waters are an attempt to normalise proximity operations. A contiguous zone extends 12 nautical miles beyond a nation’s territorial sea, which itself reaches 12 nautical miles from the coastline. While foreign warships are permitted to operate within this zone under international law, meaning the Chinese Coast Guard’s presence does not constitute a legal violation, their sustained operations there are widely perceived as a deliberate provocation. Moreover, repeated, near-daily transits within the contiguous zone erode Tokyo’s ability to treat such movements as exceptional; they become part of the background operational environment that Japanese patrols must continually contend with, utilising resources and rules of engagement. That imposes steady costs on Japan’s Coast Guard and Navy (sustained patrols, maintenance, fuel, and heightened readiness) and accelerates Japan’s shift from episodic responses to persistent deterrence postures.

Politically and legally, China’s pattern exploits the ambiguity between rights in the contiguous zone and territorial sovereignty, seeking to normalise fact-on-the-water control without crossing thresholds that would trigger automatic military responses. Beijing frames these as routine “law-enforcement” operations to assert sovereignty; Tokyo frames them as coercive intrusions demanding protest and counter-patrols. This asymmetric use of coast-guard and militia-style assets exemplifies contemporary grey-zone competition; coercive, low-intensity, but cumulative in effect.

Regionally, the long consecutive day streak matters because it lowers the marginal cost for escalation upward. Regular Chinese presence near the Senkaku Islands complements other pressure tactics, airspace probes, naval sorties near Taiwan, and expanded CCG capabilities, creating friction points where miscalculation can rapidly escalate. It also complicates burden-sharing among the United States (US) allies. Washington has reiterated security commitments to Japan, but the lines between law enforcement and collective defence remain politically and legally sensitive. The most immediate policy response is expected to involve deeper operational coordination—across Intelligence, Surveillance, and Reconnaissance (ISR) sharing, joint exercises, coast guard cooperation—between Japan, the US, and regional partners.

Politically and legally, China’s pattern exploits the ambiguity between rights in the contiguous zone and territorial sovereignty, seeking to normalise fact-on-the-water control without crossing thresholds that would trigger automatic military responses.

Domestically in Japan, the streak accelerates political pressure for sterner deterrence measures, which include increased coast-guard funding and control guidelines, possibly rules for Japan Maritime Self-Defence Force (SDF) support to and coordination with the coast guard, and potential legal adjustments to deter future coercion. It also fuels public anxiety and political narratives about national sovereignty that can constrain Tokyo’s diplomatic flexibility.

Strategically, this episode highlights a troublingly familiar trend that has become increasingly commonplace in recent years, in which maritime coercion is deployed as the tool of choice for shaping status quo outcomes without resorting to a direct conflict. The end of the 335-day streak is therefore a pause, not a reversal. Unless Tokyo and its partners raise the marginal cost of sustained grey-zone operations through a deterrent posture, legal and diplomatic pressure, and coordinated coast guard capacity building across the region, Beijing will retain the incentive to redeploy similar campaigns elsewhere or return to the Senkaku Islands on a new timetable. The policy task for Tokyo and partners is to convert episodic protest into resilient, cost-imposing responses that close the operational gaps China currently exploits, while keeping escalation paths tightly managed.

Pratnashree Basu is an Associate Fellow at the Observer Research Foundation.

• International Affairs
• China
• East Asia
• china coast guard vessels
• china japan relations
• chinese marine surveillance vessels
• chinese maritime activities south china sea
• chinese vessel in senkaku
• east china sea dispute
• japan maritime self defence force
• senkaku islands
• senkaku islands dispute

The views expressed above belong to the author(s). ORF research and analyses now available on Telegram! Click here to access our curated content — blogs, longforms and interviews.

PREV NEXT