The pedestrian tunnel is an unromantic concrete tube — but the experience of walking from Kyushu to Honshu beneath the strait, with a marked prefectural boundary at the mid-point, is one of the more memorable small adventures available in the area. The walk takes about fifteen minutes one way, and is mostly flat once you have ridden the lift down from each entrance.
The Kyushu entrance is at Mekari, about a kilometre walk west along the shore from the Mojiko Retro district. Plan around half a day for the round trip, allowing time for lunch in Shimonoseki — fugu (blowfish) restaurants are the local speciality.