Preliminary results from last year's national census show that Japan's population fell by nearly 3.1 million from the previous survey conducted five years earlier.

According to the results released on May 29, the country's population as of October 1, 2025, stood at 123,049,524, down 3,096,575, or 2.5 percent from 2020.

These are the largest declines on record, both in number and rate.

By prefecture, the population grew in Tokyo and Okinawa, but all 45 other prefectures saw declines.

Saitama and Chiba prefectures, both neighboring Tokyo, experienced population decreases for the first time since the census began in 1920.

The prefecture with the largest population was Tokyo with about 14.25 million people, accounting for 11.6 percent of the total.

Tottori in western Japan had the smallest population at approximately 520,000.