William Amakusa City is a nice place to visit, even in winter. Once making the trek down there, scenic walks are aplenty. There is an islet called Kameshima (亀島, pictured) near Wakamiya swimming beach (若宮海水浴場) which is accessible on foot by a sand spit at low tide. There is the must-visit Tomioka (富岡), a stubby peninsula topped by an eponymous (rebuilt) castle which was historically pivotal several times (Japanese Wikipedia entry: https://tinyurl.com/3yzfenfv). There is also the prefecture’s only pedestrian lift bridge (hōkaibashi, 昇開橋). Locals who want to cross the narrow strait had had to use the immensely tall, heavily trafficked road bridge (seen in the background) but can safely, calmly, and quickly zip back and forth. Kumanichi reports that the bridge has broken down and cannot be repaired until a particular part (I think it’s called a “widget”) is sourced, which is apparently difficult, so resident pedestrians are now forced to cross the tall bridge. However, photos of the bridge itself seem worth a good daytrip, even in winter. (Pro tip: there’s a Joyful at the southern base of the big bridge for breakfast or lunch.) https://kumanichi.com/articles/910588