Population and Migration in Numbers: Karatsu and Saga

Population and migration in Karatsu and Saga, in numbers

This page lists official statistics from the national government, Saga Prefecture and Karatsu City on population, births and deaths, people moving in and out, future projections, and migration consultations and new residents. Karatsu City had 110,110 residents on 1 October 2025, 6.19% fewer than in 2020. Saga City, the prefectural capital, is shown in the same tables for comparison.

This page was compiled by Karatsu Farm & Food as part of the Karatsu Data Bank. It lists only the figures and statements found in the sources, without conclusions or evaluations. Moves from other municipalities within Saga Prefecture are treated as migration on this page and shown separately from moves from outside the prefecture. Figures with different periods, coverage or definitions are kept in separate tables. No values have been read off charts.

World and Japan

The UN's World Population Prospects 2024 (UN WPP 2024) estimates the world population at 8,126,964 thousand on 1 January 2024 (Annex Table A2) and projects a peak of around 10.3 billion in the mid-2080s (p.VII).

Japan's population was 122,972,528 in the 2025 Population Census (1 October 2025), down 3,173,571 (2.5%) from 2020 (Statistics Bureau, p.7). The Statistics Bureau's monthly estimate puts the total population at 122.65 million on 1 September 2026 (provisional), 540,000 fewer than a year earlier (Statistics Bureau).

	2020	2025	Five-year change	Rate
Japan	126,146,099	122,972,528	−3,173,571	−2.52%
Saga Prefecture	811,442	780,675	−30,767	−3.79%
Saga City	233,301	227,580	−5,721	−2.45%
Karatsu City	117,373	110,110	−7,263	−6.19%

Saga Prefecture, Saga City and Karatsu City (census)

In the final 2025 census figures, Saga Prefecture had 780,675 residents, Saga City 227,580 and Karatsu City 110,110 (Table 1-1). Saga Prefecture had 832,832 in 2015 and 811,442 in 2020 (Statistics Bureau, p.7). Karatsu City had 44,471 households (Karatsu City).

Saga Prefecture's estimated population (preliminary census counts plus monthly births, deaths and moves) was 775,388 for the prefecture, 226,337 for Saga City and 108,882 for Karatsu City on 1 September 2026 (Saga Prefecture). The prefecture says it plans to update the estimates on the basis of the final census results (prefecture's estimate page).

	Under 15	15-64	65 and over	Number aged 65+
Saga Prefecture	12.5%	55.3%	32.2%	251,094
Saga City	12.5%	58.0%	29.5%	67,149
Karatsu City	12.6%	52.7%	34.8%	38,299

Age structure

In 2025, people aged 65 and over made up 32.2% of Saga Prefecture, 29.5% of Saga City and 34.8% of Karatsu City (Table 2-7). Saga Prefecture's share rose from 30.6% in 2020 and ranks 25th highest among the 47 prefectures (Statistics Bureau, p.25).

Area	2020	2025	Change	Rate
Former Karatsu City	74,749	71,497	−3,252	−4.35%
Former Hamatama	11,140	11,415	+275	+2.47%
Former Nanayama	1,851	1,540	−311	−16.80%
Former Kyuragi	3,745	3,253	−492	−13.14%
Former Ouchi	6,948	6,085	−863	−12.42%
Former Kitahata	4,130	3,762	−368	−8.91%
Former Hizen	5,943	4,990	−953	−16.04%
Former Chinzei	4,974	4,268	−706	−14.19%
Former Yobuko	3,893	3,300	−593	−15.23%

Karatsu City by area

The census also tabulates population within the boundaries of the former municipalities (Table 1-1). Of Karatsu City's nine areas, only former Hamatama grew between 2020 and 2025 (from 11,140 to 11,415); the other eight declined.

	Births	Deaths	Natural change	In-migrants (from within / outside the prefecture)	Out-migrants (to within / outside the prefecture)	Social change	Total change
Saga Prefecture	4,715	11,327	−6,612	19,260 (from outside)	18,972 (to outside)	+288	−6,324 (−8.03‰)
Saga City	1,309	3,011	−1,702	8,611 (2,414 / 6,197)	8,085 (2,177 / 5,908)	+526	−1,176 (−5.15‰)
Karatsu City	613	1,818	−1,205	2,700 (646 / 2,054)	2,976 (687 / 2,289)	−276	−1,481 (−13.28‰)

Births, deaths and moves (prefectural annual report)

According to Saga Prefecture's migration survey (Saga annual report), in the year from October 2024 to September 2025 Karatsu City recorded 613 births and 1,818 deaths, a natural change of −1,205. 2,700 people moved in (646 from within the prefecture, 2,054 from outside) and 2,976 moved out (687 within the prefecture, 2,289 outside), a social change of −276. Per 1,000 population, in-migration was 24.2 and out-migration 26.7.

Saga City recorded a natural change of −1,702 and a social change of +526. 8,611 people moved in (2,414 from within the prefecture, 6,197 from outside) and 8,085 moved out (2,177 within, 5,908 outside); per 1,000 population, 37.7 in and 35.4 out. The report states that ten municipalities, including Karatsu City (276) and Takeo City (196), had more people moving out than in.

	In-migrants	of which from within Saga	Out-migrants	Net migration
Saga Prefecture (moves with other prefectures)	15,834	−	16,985	−1,151
Saga City	7,550	2,469	7,495	+55
Karatsu City	2,485	637	2,787	−302

People moving in and out (resident register)

In the national Report on Internal Migration (2025), 2,485 people moved into Karatsu City (including 637 from other municipalities in Saga Prefecture; Table 10) and 2,787 moved out, for net migration of −302 (Table 11-1, Table 11-2, Table 11-3). Saga City had 7,550 in-migrants (including 2,469 from within the prefecture) and 7,495 out-migrants, net +55.

For Saga Prefecture as a whole, 15,834 people moved in from other prefectures and 16,985 moved out, net −1,151 (outline, p.8, Table 7); −1,208 for Japanese nationals only (p.15, Table 12). The same report's "social change" figure (net domestic migration plus moves from abroad minus moves abroad, plus moves from unknown addresses, minus deletions by authority) is +204 for Saga Prefecture (p.3, Table 2).

Net migration in the resident register (calendar 2025, domestic moves only), social change in the resident register (including moves abroad, unknown addresses and deletions by authority) and social change in the prefectural annual report (October 2024 to September 2025, including moves abroad) cover different periods and moves, so their values and even their signs differ. This page does not compare them with each other.

Age	Saga Prefecture	Saga City	Karatsu City
0-4	+177	+89	−4
5-9	+101	+82	+13
10-14	+39	+45	0
15-19	−606	−92	−123
20-24	−1,174	−217	−208
25-29	−361	−192	−41
30-34	−111	+49	−43
35-39	+139	+63	−10
40-44	+136	+81	+4
45-49	+59	+40	+23
50-54	+75	+18	+7
55-59	+70	−5	+21
60-64	+108	+13	+22
65 and over	+197	+81	+37
Total	−1,151	+55	−302

Net migration by age

In 2025, Saga Prefecture's net migration was −606 for ages 15-19, −1,174 for 20-24 and −361 for 25-29, while ages 35-39 were +139 and ages 0-4 +177 (Table 3-3). Karatsu City was −208 for ages 20-24 and −123 for 15-19; Saga City was −217 for 20-24 and −192 for 25-29 (Table 11-3).

	Previous address (top 5)	New address (top 5)
Saga Prefecture	Fukuoka 6,130, abroad 3,405, Nagasaki 1,859, Tokyo 822, Kumamoto 806 (total 19,260)	Fukuoka 7,178, abroad 1,616, Nagasaki 1,473, Tokyo 1,284, Kumamoto 883 (total 18,972)
Saga City	Fukuoka 1,737, abroad 1,074, Nagasaki 459, Chiba 378, Tokyo 334 (total 6,197)	Fukuoka 2,124, Tokyo 500, abroad 450, Nagasaki 406, Kumamoto 316 (total 5,908)
Karatsu City	Fukuoka 796, abroad 227, Nagasaki 157, Tokyo 97, Kumamoto 74 (total 2,054)	Fukuoka 1,020, Tokyo 154, abroad 154, Nagasaki 149, Osaka 91 (total 2,289)

Where people come from and go to

According to the prefectural report, of the 2,054 people who moved to Karatsu City from outside Saga Prefecture, 796 came from Fukuoka Prefecture and 227 from abroad. Of the 2,289 who moved out of the prefecture, 1,020 went to Fukuoka Prefecture and 154 each to Tokyo and abroad (Saga annual report, Tables 8 and 9).

	Moved in from abroad	of which foreign nationals	Moved abroad	of which foreign nationals
Saga Prefecture	3,391	3,008	1,697	1,346
Saga City	1,108	979	478	374
Karatsu City	243	190	172	136

As of	Foreign residents in Saga Prefecture
End of 2022	7,919
End of 2023	9,764
End of 2024	11,358
End of 2025	12,841
End of June 2026	13,508

Moves from abroad and foreign residents

In the Report on Internal Migration (2025), 243 people moved to Karatsu City from abroad (190 of them foreign nationals) and 172 moved abroad (136 foreign nationals) (Table 90). Saga City had 1,108 moves from abroad (979 foreign nationals) and 478 moves abroad.

According to the Immigration Services Agency, Saga Prefecture had 13,508 foreign residents at the end of June 2026, up from 7,919 at the end of 2022 (Immigration Services Agency). By status at the end of 2025: Technical Intern Training 3,703, Specified Skilled Worker 2,864, Student 1,651, Permanent Resident 1,204, and Engineer/Specialist in Humanities/International Services 812 (end of 2025, Table 6).

	2020 (census)	2035	2050	Aged 65+ in 2050
Saga Prefecture	811,442	720,207	620,873	39.3% (243,966)
Saga City	233,301	215,778	194,311	37.4% (72,743)
Karatsu City	117,373	97,754	80,289	41.9% (33,644)

Future population (projection)

The 2023 projection of the National Institute of Population and Social Security Research (IPSS) puts Karatsu City at 97,754 in 2035 and 80,289 in 2050, with 41.9% aged 65 and over in 2050. Saga City is projected at 194,311 in 2050 (37.4% aged 65+), and Saga Prefecture at 620,873 (39.3%). The projection is based on the 2020 census.

Item	Value	What is counted
Migration consultations (Saga Prefecture and its municipalities, desks and events)	FY2024: 4,395 (desks 3,928, events 467). FY2023: 5,041	National survey by MIC; includes phone and email
Consultations at Saga Prefecture's migration desks	FY2025: 1,499 in total (previous year: 1,330)	Only the prefecture's desks in Tokyo and Saga
New migration consultations, Karatsu City	FY2025: 214	Karatsu City policy results report
Karatsu comprehensive plan indicator "migration consultations"	1,201 (baseline, in principle FY2023) → 1,450 (target, FY2029)	Third Karatsu City Comprehensive Plan; counted differently from the line above
Karatsu comprehensive plan indicator "moves via the vacant house bank"	11 (baseline) → 20 (target, FY2029)	Third Karatsu City Comprehensive Plan

Migration consultations

According to a national survey (MIC), migration desks and events run by Saga Prefecture and its municipalities handled 4,395 consultations in FY2024 (5,041 in FY2023), out of 433,810 nationwide. Saga Prefecture's settlement report (Saga settlement report) puts consultations at the prefecture's own desks in Tokyo and Saga at 1,499 in FY2025. Karatsu City's comprehensive plan (Karatsu comprehensive plan) targets 1,450 migration consultations and 20 moves via the vacant house bank in FY2029.

Fiscal year	New migration consultations	People who moved in
FY2018	67	13 (7 households)
FY2023	207	95 (49 households)
FY2024	221	100 (52 households)
FY2025	214	86 (43 households)

New residents counted by Karatsu City

Karatsu City's FY2025 report on the results of major policies (Karatsu policy results report) gives the number of people who moved in as 86 people in 43 households in FY2025, 100 (52 households) in FY2024 and 95 (49 households) in FY2023. New migration consultations numbered 214 in FY2025. The city writes that the figures have been "roughly flat, but well above the pre-COVID FY2018 results (67 consultations, 13 people in 7 households)" (our translation).

City	Indicator (as named in the source)	Values	What is counted (per source)	Source
Saga City	Moves from the Tokyo area using grants	FY2022: 10 / FY2023: 15 / FY2024: 9 cases	Number of national regional revitalisation migration grants paid (moves from the Tokyo area)	FY2023 evaluation, FY2024 evaluation, FY2025 evaluation
Saga City	Moves from outside Saga Prefecture using grants	FY2022: 4 / FY2023: 13 / FY2024: 36 cases	Number of Saga living start-up grants paid (moves from outside the prefecture)	FY2023 evaluation, FY2024 evaluation, FY2025 evaluation
Imari City	Migration and settlement promotion project, applications, total	FY2023: 148 people (90 households) / FY2024: 104 (65) / FY2025: 104 (53)	Total applications for the migration grant, the Imari living start-up grant, migration incentives and similar (includes support for people from outside the city taking jobs in the city)	FY2023, FY2024, FY2025
Ureshino City	Migrants supported by the city or prefecture (relocation incentives, migration support, vacant house bank users, etc.)	FY2022: 227 / FY2023: 165 / FY2024: 159 people	Counted from the vacant house bank register, the migration incentive ledger, Saga living start-up and the regional revitalisation migration grant	Ureshino City
Kashima City	Households that moved in using the vacant house bank, regional revitalisation migration support, etc.	FY2023: 9 / FY2024: 7 / FY2025: 6 households	As named	Kashima City

Migration figures published by other cities in Saga Prefecture

In the documents of Saga, Imari, Takeo, Kashima, Ogi, Ureshino, Taku, Tosu and Kanzaki cities, we found no city that, like Karatsu, publishes the number of people who moved in as a result of its migration consultation service. What is published is mainly the number of cases, households or people using support schemes. Saga City's figures are counts of national and prefectural migration grants paid and do not show the total number of people moving to the city. Ogi's indicator, cumulative migration and settlement support cases, does not say what is counted (Ogi City). Taku's users of the settlement incentive (Taku City), Kanzaki's uses of the settlement housing subsidy (Kanzaki City) and Takeo's settled households (Takeo City) count settlement subsidies and do not say whether only people who moved in are counted, so they are not included. Tosu's indicator is in-migrants aged 25-39, not a count of support schemes, so it is not included either (Tosu City).

Item	Spending (JPY)
Migration concierge	6,664,948
Promotion and information	560,500
Regional revitalisation migration grant (Tokyo area, 1 case)	2,000,000
Karatsu living start-up grant (outside the Tokyo area, transitional, 3 cases)	2,200,000
Karatsu migration support grant (outside the Tokyo area, from FY2025, 3 cases)	3,000,000
Encouraging settlement	33,260
Other administrative costs	119,275
Total	14,577,983

Karatsu City's spending on migration

According to the same report, the FY2025 budget for migration and settlement promotion was JPY 35,198,000 initially, reduced by JPY 10,439,000 in a supplementary budget and by JPY 1,200,000 through reallocation to JPY 23,559,000; spending was JPY 14,577,983 (41.4% of the initial budget, 61.9% of the final budget). Spending includes JPY 6,664,948 for the migration concierge and three grants to people who moved in (JPY 7,200,000 and 7 cases in total; our calculation).

The migration concierge is outsourced by the city to a private organisation (Karatsu City). The FY2024 Karatsu migration concierge service was awarded as a single-source negotiated contract (Local Autonomy Act Enforcement Order, Article 167-2(1)(ii)) for JPY 7,106,000 including tax, for April 2024 to March 2025. The contractor's name and the city's stated reason for the negotiated contract are published on the city's page (Karatsu contract notice).

Interest in moving, preferred destinations, regional cooperators and "related population"

In a Cabinet Secretariat survey of people in their twenties living in the Tokyo area (October 2024, Cabinet Secretariat), 40.3% said they were interested (strongly or somewhat) in moving to a regional area, and 47.8% of those from outside the Tokyo area (p.17). In the Furusato Kaiki Support Center's 2025 ranking of preferred destinations (Furusato Kaiki Support Center), Saga Prefecture ranked 18th among seminar participants and was outside the top 20 among people consulting at its desk.

According to MIC, there were 8,196 Local Vitalization Cooperators nationwide in FY2025, and 45 in 16 local governments in Saga Prefecture, including the prefecture itself (2 in Karatsu City). Of cooperators whose terms ended between FY2020 and FY2024, 70.3% nationwide and 68.3% in Saga Prefecture settled in the same area (MIC). MLIT estimates the "related population", people with a continuing connection to a particular area, at about 22.63 million, about 22% of people aged 18 and over (from a 2023 online survey; MLIT).

Frequently asked questions

Q1. What is the population of Karatsu City?

The final count of the 2025 Population Census is 110,110, down 7,263 (6.19%) from 117,373 in 2020. Saga Prefecture's monthly estimate puts it at 108,882 as of 1 September 2026.

Q2. Do more people move into Karatsu or out of it?

In Saga Prefecture's migration survey (October 2024 to September 2025), 2,700 people moved into Karatsu and 2,976 moved out, a net social change of −276. In the national Report on Internal Migration (2025, domestic moves only), in-migrants numbered 2,485, out-migrants 2,787, and net migration −302. The two statistics cover different periods and moves.

Q3. What is net migration by age?

In the Report on Internal Migration (2025), Karatsu's net migration was −208 for ages 20-24 and −123 for ages 15-19. For Saga Prefecture as a whole it was −1,174 for ages 20-24, −606 for 15-19 and −361 for 25-29.

Q4. How does Karatsu compare with Saga City?

Between the 2020 and 2025 censuses, Saga City's population fell 2.45% and Karatsu's 6.19%. In the prefectural migration survey (October 2024 to September 2025), Saga City's net social change was +526 (+237 within the prefecture, +289 with other prefectures and abroad) and Karatsu's −276 (−41 and −235). Natural change was −1,702 in Saga City and −1,205 in Karatsu (the within/outside split is our calculation from Table 5).

Q5. How much does Karatsu City spend on attracting new residents, and how many people moved in?

According to Karatsu City's FY2025 report on the results of major policies, spending on migration and settlement promotion was JPY 14,577,983 (initial budget JPY 35,198,000), including JPY 6,664,948 for the migration concierge. The report gives 86 people in 43 households who moved in for FY2025 (listed as a result of the migration concierge), 100 (52 households) for FY2024 and 95 (49 households) for FY2023. These are not resident-register in-migration figures.

Q6. What is Karatsu's projected future population?

The National Institute of Population and Social Security Research (2023 projection, medium fertility and mortality) projects Karatsu's population at 97,754 in 2035 and 80,289 in 2050, with people aged 65 and over making up 41.9% in 2050. Saga City is projected at 194,311 in 2050 (37.4% aged 65 and over).

Source ledger

What this page does not cover

Saga Prefecture's policy indicator "migrants from outside the prefecture" (settlement report) is not included, because the source does not state who is counted as a migrant or whether the figures are for calendar or fiscal years. A "cost per migrant" is not calculated, because spending includes grants paid to the migrants themselves. The page does not cover reasons for population change, the effects of policies, or evaluations of municipalities or organisations. Private analyses (such as lists of municipalities "at risk of disappearing"), figures from news reports, values read off charts, and figures that could not be checked against primary sources are not included, nor are the results of our own projects. Japanese sources are summarised in our own translation; the original wording prevails.

About this page

Compiled by Hiroaki Kojima, Vice Director, Karatsu Farm & Food / Contact: kojima@karatsu-f-f.com (contact page) / Published: October 17, 2026 / Markdown: en/population-data.md

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Related links

▶ Karatsu Data Bank
▶ Tourism in numbers
▶ 人口と移住の統計（日本語）