The Kanmon Pedestrian Tunnel runs 780 metres beneath the Kanmon Strait, connecting Shimonoseki on Honshu with Moji on the Kyushu side. Access is by elevator from the Mimosusogawa-cho entrance on the Shimonoseki waterfront, about 2km east of Shimonoseki Station. The crossing is free for pedestrians; cyclists pay 20 yen and must wheel their bikes.
The tunnel is lit, clean, and perfectly safe. The walk takes about 15 minutes. On the Kyushu side you emerge at Moji port, a handsome Meiji-era waterfront district in Kitakyushu worth an hour or two on its own.