Shimonoseki is located at the westernmost of Honshu, the main island. About 680 miles southwest of Tokyo, 50 miles east of Fukuoka.

The southwestern part of the city faces Kanmon strait viewing Kyushu, the next island, less than 1/2 mile apart. Kanmon bridge spans the strait linking the two islands. Other two sides of the city, western and southern parts, are surrounded by the sea, which have scenic beaches, fisherman's communities and new development areas. Inland of the city has typical Japanese landscape with hills, valleys, ponds, rice fields and so on.