data japan 2024The 2025 population density in Japan is 338 people per Km2 (875 people per mi2), calculated on a total land area of 364,555 Km2 (140,755 sq. miles). Largest Cities in Japan City NamePopulation, total - Japan ( 1 ) United Nations Population Division. World Population Prospects: 2025 Revision; ( 2 ) Statistical databases and publications from national statistical offices; (