📉 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). Stack it against Yokohama, Japan's second-biggest city at 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 number 21.24 million, or 17.2%, 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 10.9%, a record low. Nearly one in three people is a senior; barely one in nine is a child. The pyramid is setting top-heavy.

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: 0.80 children per woman in 2025, provisionally. That is a second straight annual rise from the record low of 0.72 in 2023, yet Korea remains the only OECD member below 1. The uptick owes mostly to a wave of marriages postponed during the pandemic; births rose 6.8% in 2025, to 254,500. Regional gaps are wide, with Seoul lowest at 0.58 in 2024. The share of Koreans over 65 passed 20% that same year. Seoul has poured hundreds of billions of dollars into cash payments, housing perks, parental leave, and fertility treatment since 2008, and has gone as far as letting families hire foreign nannies. 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 the EU's oldest country, with 24.7% of its people over 65 and a fertility rate that slid to 1.14 in 2025. Births that year came to 355,000, the fewest since unification in 1861, against 652,000 deaths: a natural loss of roughly 296,000 in twelve months. And yet the population on January 1, 2026 stood at 58.94 million, essentially flat, ending the slide that began at the 2014 peak. What stopped it was not births but migration. Foreign nationals now number 5.56 million, about 9.4% of residents, and ISTAT warns the decline will resume the moment inflows thin. Prime Minister Giorgia Meloni frames the birth rate as a national priority, with policy leaning toward supporting large families rather than coaxing first births. 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 now shrunk for four straight years, at a widening pace: down 3.39 million in 2025 alone, roughly 7.7 million over the four years combined. It ceded its "most populous" title to India in 2023. Births fell 17% in 2025, to 7.92 million, the fewest since records began in 1949, and the fertility rate sank to 0.96, 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 climbed back to where it was. Korea's two-year uptick is one of the few bright spots, and 0.80 is still nowhere near the 2.07 replacement level. 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. Under its "acceleration plan" for children and child-rearing, the government is phasing in an extra ¥3.6 trillion a year (roughly $24 billion at ¥150 to the dollar) by fiscal 2028: 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. Foreign residents numbered 4,125,395 at the end of 2025, up 9.5% in a year and above four million for the first time, or 3.36% of the population. That 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?

Note: Japan's population figures here come from the preliminary tabulation of the 2025 census, released May 29, 2026. The confirmed basic tabulation is due around September 2026 and may shift the numbers slightly.

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