Kumamoto Prefecture: Airport Access Railway Estimated at ¥61 Billion, Agreement with JR Kyushu on Separation of Ownership and Operations
September 24, 2025 – Construction & Planning
On September 22, Kumamoto Prefecture announced that the estimated cost of the Aso Kumamoto Airport Access Railway, branching from Higo-Ōzu Station on the JR Hōhi Main Line, is approximately ¥61 billion. The increase of about ¥20 billion compared to the 2022 estimate reflects rising construction costs. An additional ¥6 billion is required for improvements to the Hōhi Main Line, such as double-tracking.
The prefecture also revealed that, following discussions with JR Kyushu, the project will adopt a vertical separation model, splitting the roles of railway ownership and operations.
During a session of the prefectural assembly, Governor Takatoshi Kimura provided further details. Initial forecasts in 2022 projected 4,900 daily passengers, but refined demand estimates now suggest approximately 6,500 daily users. The benefit–cost ratio (B/C) has increased from 1.03 to 1.21, exceeding the threshold of 1 for project viability.
Preparations are underway for establishing a corporate entity to oversee construction, alongside discussions with the national government for railway project approval.
Governor Kimura emphasized, "This project is essential for further development, positioning our prefecture at the center of Silicon Island Kyushu." He added that with cost reviews and progress in discussions with JR Kyushu, "the mission of constructing the airport access railway has advanced significantly. We will work to start construction in FY2027."
The airport access railway will be a single-track line approximately 7 km in length. In June, a route corridor approximately 500 meters wide was presented. The line will run south from Higo-Ōzu via embankments and elevated viaducts, pass through the Takayubaru Plateau via tunnel in the midpoint section, and connect to an airport station on the south side of the airport. The urban planning decision is targeted for FY2026, with land acquisition and railway construction to begin in FY2027, and an opening planned by the end of FY2034.
