Russian Corvette 'Gremyashchiy' Transits Japan's Tsugaru Strait, Monitored by JMSDF

Russian Corvette Detected in Tsugaru Strait

On Sunday, February 1, 2026, a modern Russian Navy corvette, identified as the Gremyashchiy (hull number 337), transited eastward through the Tsugaru Strait, a key international waterway separating Japan's Honshu and Hokkaido islands. Japan's Ministry of Defense (JMOD) confirmed the transit on February 2, 2026, noting that the vessel proceeded into the Pacific Ocean.

The Gremyashchiy was first detected around 8:00 a.m. local time, approximately 130 kilometers west of Tappi Cape in Aomori Prefecture, moving in a southeastward direction before entering the strait.

Japan's Surveillance and the Tsugaru Strait's Status

The Japan Maritime Self-Defense Force (JMSDF) actively monitored the Russian corvette's passage. Surveillance and intelligence collection were conducted using the escort ship Chikuma, assigned to the 15th Escort Division based in Ominato, and a P-3C Orion maritime patrol aircraft from the 2nd Air Group at Hachinohe. Japanese officials emphasized that the operation was limited to monitoring and data gathering, confirming that the Russian vessel did not violate Japan's territorial waters or airspace.

The Tsugaru Strait is recognized as an international waterway, connecting the Sea of Japan with the Pacific Ocean. Notably, Japan maintains a narrower territorial sea claim of three nautical miles (5.6 km) in certain international straits, including the Tsugaru Strait, instead of the standard twelve nautical miles. This arrangement ensures a corridor of international waters, allowing for the unimpeded passage of vessels.

Vessel Specifications and Regional Context

The Gremyashchiy is a Steregushchiy III–class corvette, part of Russia's Project 20385, which represents an improved variant of the Steregushchiy-class surface combatants. These vessels are designed for multi-role operations, encompassing surface warfare, anti-submarine missions, and air defense. They are equipped with guided missiles and modern sensor suites, with the capability to carry advanced weaponry such as the hypersonic 3M22 Zircon anti-ship cruise missiles.

This transit underscores the ongoing pattern of Russian naval activity near the Japanese archipelago. Such movements are routinely tracked by Tokyo as part of its maritime domain awareness efforts, reflecting the continued high intensity of Russian Pacific Fleet operations in the northern waters of Japan throughout 2026.