Sakurajima, the most volcanic island in Japan, can be easily accessible from downtown Kagoshima by ferry. If you rent an electric bike on the island, you can cycle around the perimeter in four hours. Enjoy the ocean view on the left side of the road. The volcanoes can be seen on the right side of the road towards the end of the trip.
English caption is available.
Railroad Journeys in Japan playlist: https://youtube.com/playlist?list=PLp2vxuJ_2xypoW9wtU7JeIbEkftF53B48
More info about this trip:
Rainbow Sakurajima (bike rental)
https://www.qkamura-s.com/sakurajima/
Sakurajima Ferry
https://www.city.kagoshima.lg.jp/sakurajima-ferry/index.html
Tenmonkan Mujaki (shaved ice)
https://mujyaki.co.jp/