Minami Bōsō Quasi-National Park is a quasi-national park in the Kantō region of Honshū in Japan. It is rated a protected landscape according to the IUCN. The park includes numerous widely separated portions of the coastal areas of southern Bōsō Peninsula, ranging from Cape Futtsu on Tokyo Bay to the west, to Cape Inubō facing the Pacific Ocean in the east. A portion of the park, located offshore the city of Katsuura has been designated as an underwater marine park since June 7, 1974.