Japan Population Falls More Than 3 Million in Five Years

japan’s population fell to 123 million in 2025, down from 126.1 million in 2020, according to preliminary census results released on Friday. The drop of more than 3 million was the biggest since the government began collecting census data in 1920.

For residents outside Tokyo, the numbers point to a country where school rolls, hospital staffing and train service are already under strain in many places. James Raymo, a Princeton University professor of sociology who studies Japan, said the decline cannot be reversed in the short or medium run without mass immigration.

Tokyo and Japan’s shrinking prefectures

All but two of Japan’s 47 prefectures reported population decreases in 2025, a sign that the fall is not limited to one region. Akita and Aomori saw their populations shrink by about 8 percent from 2020 to 2025, while the Tokyo metropolitan area rose slightly to 37 million and accounted for roughly 30 percent of Japan’s total population.

The contrast inside Japan is stark. Tokyo is about 20 times as dense as the rest of Japan, and the pull toward the capital continues to draw people from rural areas even as the countryside loses residents, schools, hospitals and train lines.

James Raymo on Japan’s decline

Raymo said, "Japan has now reached a level where this kind of decline is not reversible in the short- or medium-run". He added, "It simply will not happen in the absence of mass immigration."

The figures show why that assessment is so blunt. Japan has one of the world’s lowest birth rates, with two deaths for every new birth, while women in Okinawa give birth to an average of 1.5 children in their lifetimes compared with 1.1 nationally.

Japan’s path to 2070

Japan’s population peaked at 128 million in 2008 and is projected to fall to 87 million by 2070. The country was roughly the same size in 1989 as it is now, but the latest census results show how quickly the decline has accelerated.

For Japan, the immediate pressure is practical rather than abstract: fewer workers, fewer children in classrooms, and more places where the population base is no longer large enough to sustain services at the same scale. The next benchmark will be how policymakers respond to the latest census results as the demographic squeeze spreads beyond the big cities.