📉 In five years, Japan lost more people than live in the entire city of Osaka.

The 2025 census puts the population at 123 million — about 3.1 million fewer than in 2020, the steepest five-year fall since counting began in 1920. The country also slipped from 11th to 12th in the world, overtaken by Ethiopia. Here's what that number actually looks like on a map, and how South Korea, Italy, and China are staring down the same cliff.

A whole city, gone in five years

Big demographic numbers tend to slide off the brain. "Down 3.1 million" sounds like a statistic. So picture it as a place.

The exact figure is a loss of 3,096,575 people between the 2020 and 2025 censuses. That is more than the entire population of Osaka, Japan's third-largest city, which sits at about 2.76 million. It's roughly the size of Buenos Aires proper (around 3.1 million), or close to Busan, South Korea's second city (about 3.4 million in its metro core). Stack it against Yokohama — Japan's second-biggest city, 3.77 million — and the loss equals more than four out of every five residents.

Now run the clock. That works out to about 620,000 people a year, roughly 52,000 a month, around 1,700 every single day. Every morning, Japan wakes up with the equivalent of a small town fewer than the day before — and the pace is accelerating.

Between 2015 and 2020, the population fell 0.7%. Between 2020 and 2025, it fell 2.5% — more than three times faster. The total is still the world's 12th largest, but the slope has clearly tipped.

Why being overtaken by Ethiopia matters

For decades Japan ranked among the ten most populous nations on Earth. In the new tally it sits 12th, having been passed by Ethiopia, whose population grew about 13.9% over the same five years that Japan's shrank.

The swap is not an insult — it's a snapshot of two demographic engines running in opposite directions. One country is young and expanding; the other is old and contracting. Rankings will keep reshuffling: Nigeria, Pakistan, and others are climbing while the wealthy, aged economies of East Asia and Europe drift down. The headline isn't really about Ethiopia. It's that Japan has become a leading example of what a rich country looks like when it stops replacing itself.

What "shrinking Japan" is actually made of

The raw decline hides two faster currents underneath.

The first is age. By government estimates, people aged 65 and over now make up about 29.4% of the population — the highest share of any country in the world. Those 75 and older are around 17%, a level reached in 2025, the year the postwar baby-boom generation had all moved into that bracket. Meanwhile children under 15 have fallen to roughly 10.9%, a record low. A country where nearly one in three people is a senior and barely one in nine is a child is, in effect, top-heavy by design.

The second is geography. In this census, 45 of Japan's 47 prefectures lost population — only Tokyo (+1.4%) and Okinawa (+0.1%) grew, and even their gains shrank. Saitama and Chiba, the commuter belts ringing Tokyo, declined for the first time ever; neighboring Kanagawa and Aichi fell for the first time since the immediate postwar years. Akita in the north lost 8.1%, the steepest rate in the country. More than 90% of all municipalities — 1,558 of them — shed residents. The pull of Tokyo hasn't loosened, but now even the capital's suburbs are draining.

One more quiet number: the average household now holds 2.15 people, a record low, as single-person living keeps rising. The country isn't only losing people; the unit it lives in is shrinking too.

Korea, Italy, China: countries walking toward the same edge

Japan's trajectory looks severe until you scan the neighborhood, where it turns out to be not alone, just early.

South Korea has the lowest fertility rate on the planet: 0.75 children per woman in 2024, and just 0.55 in Seoul. The share of Koreans over 65 passed 20% the same year. Seoul has poured hundreds of billions of dollars into cash payments, housing perks, parental leave, and fertility treatment since 2008, recently went as far as letting families hire foreign nannies, and is standing up a dedicated population ministry. The Bank of Korea's governor has called the rate a "national emergency," warning that if it holds, the country faces prolonged negative growth after 2050.

Italy is Europe's oldest country, with 23.5% of its people over 65 and a fertility rate of 1.18. Its population has fallen every year since 2014, shedding more than 1.36 million people — the equivalent of losing Milan, its second-largest city. Rome's approach leans toward supporting large families rather than coaxing first births: roughly €1 billion (about $1.1 billion) a year in tax breaks and leave, with Prime Minister Giorgia Meloni framing the birth rate as a national priority. Immigration has softened the blow — 5.4 million foreign-born residents, about 9.2% of the total — but ISTAT still projects Italy could fall to 47.7 million by 2070. Tellingly, demographers now pair Italy's decline directly against Ethiopia's growth, the same contrast Japan just lived.

China crossed into decline in 2022 and has lost nearly 36 million people since, ceding its "most populous" title to India in 2023. Its fertility rate sank to 1.01 in 2024, a collapse rooted in the one-child policy of 1979–80. Beijing has since scrapped all birth limits, rolled out a nationwide childcare subsidy of 3,600 yuan (about $500) a year per young child, and committed roughly $12.5 billion in 2025 to reach 20 million families. So far, none of it has moved the needle.

The uncomfortable pattern: no country that has fallen this far below replacement has reliably climbed back. Money helps at the margins. It has not reversed the trend anywhere.

Are Japan's countermeasures working?

Japan is leaning on three levers. The honest scorecard is mixed.

Birth support. The government now spends about ¥3.6 trillion (roughly $22.6 billion) a year on its child and child-rearing plan — expanded child allowances, a push for "dual-earning, dual-parenting" households, and pressure on companies to let fathers take leave. Births are still falling. As in Korea and China, spending has slowed the decline at best, not reversed it.

Regional revival. A decade of "regional revitalization" programs aimed to lure people and jobs out of Tokyo. The census verdict is blunt: only Tokyo and Okinawa grew, and Tokyo's own suburbs are now shrinking. The concentration the policy was built to break has, if anything, hardened.

Immigration. This is the one lever visibly moving. The foreign-resident population is rising fast — up more than 9% in the latest estimates, to around 3.9 million — and is effectively the only source of population growth Japan has left. Yet the country still avoids calling this "immigration policy," preferring the language of "foreign talent." That gap between what's happening and what's named looks set to be the central argument of the next decade.

In Japan, the conversation is shifting from "how do we grow again?" to "how do we shrink well?" — and as a major economy, it's the first one forced to answer that. Which way is your own country leaning, and has anyone there started asking the second question yet?

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