Mobara Naval Air Base

The air base was closed following the surrender of Japan at the end of World War II. As part of the terms of surrender, the Imperial Japanese military was dissolved, and its facilities, including Mobara Naval Air Base, were decommissioned and disarmed. The site was briefly controlled by Allied occupation forces before being returned to the Japanese government for civilian use.

The site of the former air base has been completely redeveloped and is now integrated into the urban fabric of Mobara city. The majority of the land, including the area of the main runway, is occupied by the large Mitsui Chemicals Mobara Branch Factory. Other parts of the former base have been converted into civic, residential, and commercial areas. Key locations on the former site include the Mobara City Central Public Hall (茂原市中央公民館) and surrounding neighborhoods. There are very few physical remnants of the airfield, but a peace monument ('Heiwa no Ishizue') has been erected near the public hall to commemorate the history of the base and honor those who served and died there.

Mobara Naval Air Base was a significant airfield for the Imperial Japanese Navy Air Service (IJNAS) during World War II. Established around 1942, its primary initial role was as a major training center for the crews of land-based medium bombers, most notably the Mitsubishi G4M ('Betty'). The Mobara Naval Air Group (茂原海軍航空隊) was based here, responsible for training pilots, navigators, and bombardiers before their deployment to front-line units across the Pacific. As the war progressed and the threat to the Japanese mainland grew, the base's function shifted. It became an operational base for home defense, launching interceptors and bombers against Allied B-29 raids. In the final, desperate months of the war in 1945, it also served as a staging point for 'Kamikaze' special attack missions, particularly those targeting the US fleet during the Battle of Okinawa. Due to its strategic importance, the base was repeatedly targeted and damaged by American air attacks.

There are no plans or prospects for reopening the site as an airport. The land has been fully repurposed for industrial, civic, and residential use for over 70 years. The original aviation infrastructure has been entirely removed, and the area is now a vital part of the city's economy and community, making any future conversion back to an airfield infeasible.