Fertility Climbed to 0.80, Seoul Sank to 0.58
South Korea's total fertility rate rose to 0.80 in 2025. It hit bottom at 0.72 in 2023, rebounded for the first time in nine years to 0.75 in 2024, and has now climbed another step. Births rose too—to 254,500, up 16,100, or 6.8%. Read the headline alone, and the mood looks like it has turned.
Yet inside the same country sits the opposite number. The Seoul Capital Area leads the nation in net youth inflow, and at its center, Seoul's total fertility rate for 2024 was 0.58—dead last nationwide. The two figures are keyed to different years—the national 0.80 is 2025, Seoul's 0.58 is a 2024 provisional figure. Seoul's rate likely ticked up slightly in 2025 too, but the standing does not change: where the most people gather, the fewest children are born.
What Built the 0.80
Start with what the rebound actually is. First births rose 8.6% in 2025, to 158,700, and the share of couples having a child within two years of marriage climbed to 36.1%. The pattern reads as marriages deferred during COVID releasing at once, pulling early births forward.
The Lift vs. the Ceiling (2025)
Figure Lift — first births +8.6% (158,700) Lift — births within 2 years of marriage 36.1% Ceiling — mothers aged 35+ 37.3% (record high) Ceiling — natural population decline −110,000 Source: National Data Agency, Birth and Death Statistics (provisional), 2025
The trouble is that ceiling. The same year, the mean age of mothers at childbirth rose to 33.8, and the share of mothers aged 35 and over hit a record 37.3%. Even in a year of more births, deaths reached 363,400 and the natural population decline ran to 110,000. The rebound is real. But it is a one-time draw on deferred births—once the echo cohort passes and the population in its early thirties shrinks, it will likely fade.
The Same Youth, Two Numbers
Total Fertility Rate by Region, 2024
- Seoul 0.58 · Busan 0.68 (big cities = bottom of the national range)
- National average 0.75
- Sejong · South Jeolla 1.03 (national high)
Source: Statistics Korea, Vital Statistics (by administrative region), as of 2024
The Seoul Capital Area has drawn net population inflows for eight straight years since 2017, and for young people alone, not a single year since 2004 has run the other way—they have only come in. In 2024 the biggest reason youth moved to the Capital Area was jobs (58,000), followed by education (16,000). Work called the young in.
One thing needs to be precise here. The magnet for the young is not "Seoul" but the "Capital Area." Seoul is closer to a transfer station—it takes them in and pushes them out to the fringe. In 2023 alone, roughly 200,000 people left Seoul for Gyeonggi and Incheon. Work in Seoul, sleep in Gyeonggi. The young arrive in the Capital Area and circle Seoul's edge.
As a result, the Capital Area's share of the population first passed the rest of the country in 2020 (50.2%) and has kept growing; it is projected to reach 53.4% by 2052. South Korea's capital concentration ranks first among 26 OECD countries.
The very place that gathers the young has the lowest fertility in the country. The temptation is to conclude at once that concentration suppresses births. But it reads the other way too. It may be the result of young people who have already deferred marriage and childbirth—unmarried, highly educated, career-oriented—converging on Seoul. The total fertility rate is sensitive to the age and marital composition of women of childbearing age. The same 0.58 can be read as "Seoul suppressed births" or as "the people who weren't going to have children live in Seoul." To tell the direction of causation apart, you have to do more of the math.
The Same Data, Four Reckonings
The economist sees concentration itself as a force pressing births down. The Bank of Korea finds that as population density rises, competition intensifies and childbearing gets pushed back. The Korea Research Institute for Human Settlements is more specific: housing prices account for 30.4% of what drives the first-birth rate, and by its estimate, a 1% rise in home prices shaves 0.002 off the fertility rate the following year. Among those who cited "insufficient funds for marriage and housing" as the main reason they had not married, the share was 32.7% in their twenties and 33.7% in their thirties. The demographer Cho Young-tae names capital concentration as a root cause of low fertility, and Professor Ma Kang-rae sees the post-2015 rush of youth to the capital accelerating in step with housing burden and falling birth rates. Still, home prices do not explain all of it. That Sejong—a new city and a youth destination—has the country's highest fertility (1.03) points to the variable being not "density itself" but "housing stability and supply." It means that where people can still buy a home, births get shaved less, even in density.
The party in question—the young themselves—traces a path that simply connects these numbers. Drawn to the Capital Area by work, pushed out to Gyeonggi and Incheon by housing costs, they defer childbirth to some later chance. Another axis overlaps this path. The decision to delay childbirth runs as much on a woman's career opportunity cost and care burden as on housing costs. This piece focuses on the housing-and-concentration axis, but let it be clear that the causation behind births is not a single real-estate variable.
Firms and the labor market keep a different reckoning again. Good jobs are agglomerated in the Capital Area, and agglomeration is itself a force that raises productivity and tax revenue. So firms respond poorly to dispersion incentives—leave the cluster, and you lose your edge. Hiring the young in the Capital Area is rational for a firm. The spatial lock-in of good jobs binds the path of the young in one direction.
The policymaker wants to read 0.80 as an achievement. But the reach of dispersion policy has to be seen honestly. Unwind concentration and you may narrow the "gap" between Seoul's 0.58 and the national 0.75—but raising the "level" of national fertility is a different matter. Even Sejong, the least concentrated, sits at 1.03, half the population-replacement line of 2.1. It means even the unconcentrated regions are, demographically, collapsing. Dispersion is a lever for narrowing the gap, not a master key to low fertility.
The Bank of Korea shows, in accounting terms, where these four reckonings meet at a single point. It is the fertility profit-and-loss of the years from 2001 to 2021, as the young left the provinces for the Capital Area.
Fertility Profit-and-Loss of Youth Migration (2001–2021 cumulative, estimate)
Item Fertility impact Youth outflow from non-Capital regions −31,000 Youth inflow to the Capital Area +25,000 Added loss from rising Capital-Area density −4,800 Net effect −10,800 Source: Bank of Korea, "Interregional Migration and the Regional Economy" (Jeong Min-soo), 2023-11-02
Births that would have happened in the provinces (low, but higher) get shaved further in the Capital Area. The births created by inflow (+25,000) do not cover those erased by outflow (−31,000), and once the density loss is added in (−4,800), the net effect is −10,800. The moment the same young person changes places, the expected value of childbirth falls. It is as if the provinces' latent births are converted, like currency, into the capital's non-births. The sum of choices rational for each individual registers as a minus in the demographic statistics.
Be honest here. Spread over twenty years, −10,800 is about 540 a year. Against annual births that have sunk into the 260,000s, that is a thin slice. Concentration is not the "main dam" of low fertility but something closer to a "marginal leak" that drops an already low rate lower. What this accounting captures is only the share attributable to migration; the equilibrium effect, by which density suppresses childbirth across all the young who stay, is separate. And as Sejong's 1.03 above already says, unwinding concentration will not revive national fertility anywhere near the replacement line. Concentration is not the variable that "creates" low fertility but an amplifier that pushes an already low rate "lower" and widens regional gaps. Even so, the direction is clear. The same person, having changed places, has fewer children.
So How Should We Read 0.80?
0.80 is not a signal that the problem is solved—it is a signal that deferred births were briefly pulled forward. Once the echo cohort passes and the population in its early thirties starts to shrink, this rebound loses its force. That the share of older mothers sits at a record high shows where that clock stands.
What to watch is not the single fertility number. Capital concentration (on a trajectory toward 53.4% by 2052), the share of cities and counties at risk of extinction (already a majority), and Seoul's fertility rate (0.58) all move together. 53.1% of the country's municipalities—121 of 228—are already extinction-risk areas, and in 2024 Busan became the first metropolitan city to enter that stage.
Misread the rebound as a trend and you misplace the bet. The moment you see 0.80 and wager on a provincial recovery, the concentration trajectory stands on the other side of that trade. Regardless of the birth rebound, the denominator of provincial assets and labor keeps draining, while the downside of Capital-Area home prices is structurally held up. Beneath the news that fertility rose, the engine pulling the young in has never once stopped.