Sasebo Airfield

The site is an active military installation (JGSDF Camp Ainoura) and is therefore 'closed' to all public and civil aviation. It was not shut down due to economic reasons, accidents, or a specific conversion event; its function has been military for many decades.

The site is an active and vital military heliport known as JGSDF Ainoura Airfield (ICAO: RJDA), located within JGSDF Camp Ainoura. It is the primary air facility for the JGSDF's Amphibious Rapid Deployment Brigade, supporting their specialized training and operations. The facility is strictly military and completely inaccessible to the public.

The airfield is located within JGSDF Camp Ainoura (陸上自衛隊相浦駐屯地). Historically, this area was a key part of the Sasebo Naval District, housing the Imperial Japanese Navy's Sasebo Marine Corps (佐世保海兵団) before and during World War II. After the war, the site was briefly used by U.S. forces before being transferred to the Japan Ground Self-Defense Force (JGSDF) in 1955. The air facility, correctly identified as JGSDF Ainoura Airfield (ICAO: RJDA), is a heliport. Its primary historical and current function is to provide air mobility and logistical support for the ground forces stationed at the camp. Its modern significance is immense, as it is the home base for the Amphibious Rapid Deployment Brigade (ARDB), Japan's elite marine unit established in 2018. The airfield handles military helicopter operations (e.g., CH-47, UH-60) crucial for the brigade's training and rapid deployment capabilities.

There are zero prospects for this facility to open as a public or civil airport. It is a critical, active military installation central to Japan's modern defense strategy, particularly concerning amphibious operations and the defense of its southwestern islands. There are no plans for its conversion.