Toshimoe Naval Floatplane Base

The initial closure as a Japanese base was due to its capture by the Soviet Union at the end of World War II. The final abandonment of the site by the Soviet/Russian military was due to a combination of military obsolescence (a strategic shift from seaplanes to land-based maritime patrol aircraft) and the extensive military downsizing and base closures that occurred after the dissolution of the Soviet Union.

The site of the former floatplane base is completely abandoned and in a state of ruin. Satellite imagery shows decaying concrete ramps leading into the water and crumbling foundations of former buildings. The area is not in any official use and is being reclaimed by nature. All modern air transport and military aviation on Iturup Island are now handled by two land-based airports: the older Burevestnik Airport (UHSB) and the new, all-weather Yasny Airport (UHSI), which opened in 2014.

The base, located in what was then known as Hitokappu Bay (now Kasatka Bay), is of major historical significance. In November 1941, it served as the secret final assembly and departure point for the Imperial Japanese Navy's carrier strike force (Kido Butai) before it sailed to attack Pearl Harbor, marking the United States' entry into World War II. During its active Japanese period, the base operated floatplanes for maritime reconnaissance, anti-submarine warfare, and local defense. After its capture by the Soviet Union in 1945, the site was likely repurposed by the Soviet Navy for similar maritime patrol duties, serving as a strategic Cold War outpost in the Pacific.

There are no known plans or prospects for reopening the Toshimoe Naval Floatplane Base. The seaplane/floatplane technology it was built for is largely obsolete for modern military applications. The Russian Federation has invested significantly in the modern, land-based Yasny Airport to ensure reliable access to the island, making the old floatplane site strategically and economically redundant.