The gap in child and older-person shares
In the Statistics Bureau's population estimates for 1 October 2024, children under 15 accounted for 8.8% of Akita's total population and 15.8% of Okinawa's. The shares aged 65 or older were 39.5% and 24.2%. Akita had the country's lowest child share and highest older-person share; Okinawa had the highest child share and the second-lowest older-person share, after Tokyo.
In Okinawa, the 15.8% under-15 share exceeded the 11.7% share aged 75 or older. It was the only prefecture where that was true. Such an age profile is the accumulation of births, deaths and moves over many years, not a result of one year's births.
Births have fallen even in younger Okinawa
Akita's population vision records 3,282 births in 2024, while Okinawa's final vital-statistics report records 11,753. Both figures count Japanese children born in Japan by the child's prefecture of residence, using the final vital-statistics series. Okinawa's count was 796 below the previous year. Because the prefectures differ in population size, the raw totals do not show where a child is more likely to be born.
Births are only one side of population change. The Statistics Bureau's estimates show more deaths than births in every prefecture, including both Akita and Okinawa, during October 2023–September 2024. Akita had the country's highest natural-decrease rate at 1.56%. Okinawa's younger profile coexists with natural decrease over that period.
Moves in and out also shape the population
The same estimates show a net social decrease in Akita and a net social increase in Okinawa for October 2023–September 2024. Social change combines moves between prefectures with international arrivals and departures; it excludes births and deaths. A separate report for domestic inter-prefecture moves in 2025 records a net outflow of 3,836 from Akita.
Moves by young people can affect both the current age mix and the number of births in later years. To understand the Akita–Okinawa difference, we would need to know which age groups arrived and left as well as how births and deaths changed. These aggregate figures do not tell us what proportion of the age-profile gap each factor explains.