Paengnyongdo Beach Airfield (Sagot Beach Airfield) (K-53)

The primary reason for its decline in regular use was military-technical obsolescence. The natural sand runway, while remarkably hard, is unsuitable for modern, heavy, high-performance jet aircraft (fighters and large transports) which require long, paved, reinforced concrete runways. Furthermore, environmental changes and natural processes have reportedly made the beach surface softer over the decades, reducing its load-bearing capacity for even older, heavy propeller transports. Its use was phased out due to a shift in military aviation technology and requirements, not for economic reasons or a specific accident.

The site currently has a dual status. Militarily, it is maintained by the Republic of Korea Marine Corps (6th Marine Brigade), which is stationed on the island, as a contingency/emergency runway and a beach assault training ground for amphibious vehicles. Regular fixed-wing aircraft operations are no longer conducted. Civically, Sagot Beach is a major tourist attraction and is protected as South Korean Natural Monument No. 391. The public can visit the beach, drive cars on its hard-packed surface (in designated areas), and appreciate its unique geological and historical significance.

Designated as K-53 by the U.S. Air Force during the Korean War (1950-1953), Paengnyongdo Beach Airfield was a crucial forward operating base. Its strategic location, as the westernmost point of South Korea near the Northern Limit Line (NLL) with North Korea, made it vital for transport, supply missions, emergency landings, and reconnaissance. The runway is the beach itself—Sagot Beach (사곶해변)—a 3km long, 200m wide stretch of fine-grained quartz and diatomaceous silt. When the tide is out, this surface becomes as hard as asphalt, allowing aircraft to land and take off. It is world-renowned as one of only two such natural beach runways historically used for regular flights (the other being Barra Airport in Scotland). After the war, it was periodically used by the Republic of Korea Air Force and Marine Corps for training and transport operations, primarily with propeller-driven aircraft like the C-46, C-123, and occasionally the C-130.

There are no plans to 'reopen' the natural beach runway for regular commercial or military aviation due to its protected status as a Natural Monument and its technical limitations. However, there is a significant and active government project to build a new, conventional airport on Baengnyeongdo Island. The project, often referred to as 'Baengnyeongdo Airport', has passed preliminary feasibility studies and has budget allocated by the central government. The plan involves constructing a new, paved runway (approximately 1,200 meters long and 30 meters wide) along with a passenger terminal and other facilities. This new airport will be designed to handle 50-seat civilian turboprop aircraft (like the ATR-42/72) and military transport planes (like the C-130). The goal is to bolster national security by allowing for rapid troop and supply deployment and to dramatically improve transportation for the island's residents and tourists, who currently depend on long and often-canceled ferry services.