The Nagasaki Main Line , or simply Nagasaki Line, is a railway line owned by the Kyushu Railway Company connecting Tosu Station in Saga Prefecture to Nagasaki Station in Nagasaki Prefecture, Japan. There is a separate branch of this line from Kikitsu Station to Urakami Station by way of Nagayo Station and the Nagasaki Tunnel, avoiding a long detour.

The Kyushu Railway Company, also referred to as JR Kyushu , is one of the seven constituent companies of Japan Railways Group. It operates intercity rail services within Kyushu, Japan and the JR Kyushu Jet Ferry Beetle hydrofoil service across the Tsushima Strait between Fukuoka and Busan, South Korea. It also operates hotels, restaurants, and drugstores across its service region. JR Kyushu's headquarters are in Hakata-ku, Fukuoka.