Projection of total population Japan 2025-2120

data japan 2023Key information about Japan population. The Japan population reached 123.7 million people in Dec 2025, compared with the previously reported fure of 124.3 million people in Dec 2025;The 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 Name