# Remote Islands in Numbers: Japan's Islands and Karatsu's Seven Inhabited Islands

Created by: Karatsu Farm&Food (NPO), Karatsu Data Bank / HTML: https://karatsu-f-f.com/en/island-data.html / Published: 2026-10-27
- People living on Karatsu's seven inhabited islands: 1,203. 2020 census; down 18.9% from 1,484 in 2015 (Saga Prefecture)
- Ferry passengers to the seven islands: 306,759. Total of seven routes over the subsidy periods (Oct 2023–Sep 2024 or Oct 2024–Sep 2025)
- Island study-abroad pupils from outside: 16. FY2025, on Takashima, Kakara, Madara and Ogawa; 14 the year before (Karatsu City)

## Karatsu's islands, in numbers

All of Saga Prefecture's remote islands are the seven inhabited islands of Karatsu City: Takashima, Kashiwajima, Ogawa, Kakara, Matsushima, Madara and Mukushima. This page lists, from national, prefectural and city documents, the number of islands and island population in Japan, and the population, ferries, schools and public spending of Saga's seven islands. In the 2020 census the seven islands had 1,203 people in 577 households ([Saga Prefecture](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001619211.pdf)).
This page is part of the Karatsu Data Bank by Karatsu Farm&Food, an NPO in Karatsu. Since FY2023 we have run environmental education with the school of one Karatsu island each year ([Island ESD](https://karatsu-f-f.com/en/island-esd.html)). The page gives no conclusions or evaluations, only the figures and statements found in the documents. Values we calculated are marked "our calculation". Values read from charts are not used. English renderings of Japanese documents are our translations; the original text takes precedence.

| Category | Islands | Population (2020) | Law (year enacted) |
|---|---|---|---|
| All islands of Japan | 14,125 | - | - |
| Remote islands (excluding Honshu, Hokkaido, Shikoku, Kyushu and Okinawa Island) | 14,120 | - | - |
| Inhabited islands | 417 | - | - |
| Areas designated under the Remote Islands Development Act | 255 (77 areas) | 339,211 | Remote Islands Development Act (1953) |
| Designated remote islands of Okinawa | 38 | 126,103 | Okinawa Promotion Special Measures Act (2002; earlier law 1971) |
| Amami Islands | 8 | 104,281 | Amami Islands Promotion and Development Special Measures Act (1954) |
| Ogasawara Islands | 4 | 2,929 | Ogasawara Islands Promotion and Development Special Measures Act (1969) |
| Not covered by the four laws above | 112 | - | - |
| Specified inhabited remote border islands (part of the 255) | 71 (15 areas) | 244,998 | Inhabited Remote Border Islands Act (2016) |

Note: Island counts as of 1 April 2026. Inhabited islands are based on the 2020 census as reported by prefectures, including Okishima, a lake island in Shiga. Population from the 2020 census: the 255 islands from MLIT's list of designated areas, Okinawa from Okinawa Prefecture (March 2026), Amami and Ogasawara from a report to the National Land Council (30 June 2026), border islands from the Cabinet Office. Law names are our translations. Sources: [MLIT, composition of Japan's islands](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001477518.pdf), [MLIT](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001886615.pdf), [Okinawa Prefecture](https://www.pref.okinawa.jp/_res/projects/default_project/_page_/001/038/825/01.chapter1.r8.pdf), [MLIT (National Land Council)](https://www.mlit.go.jp/policy/shingikai/content/002009910.pdf), [Cabinet Office](https://www.cao.go.jp/yosan/pdf/r5/03014200_naikakufu_kokai_sankou.pdf)

## How many islands Japan has, and which law covers them

Japan consists of 14,125 islands, of which 14,120 are remote islands. Of these, 255 inhabited islands lie in areas designated under the Remote Islands Development Act (1953). They span 77 areas, 26 prefectures and 111 municipalities, cover 5,313 km² (1.41% of Japan) and have 340,000 residents (0.27% of Japan) ([Ministry of Land, Infrastructure, Transport and Tourism (MLIT)](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001477518.pdf)).
Of the 417 inhabited islands, 255 are covered by the Remote Islands Development Act, 50 by separate laws for Okinawa (38), Amami (8) and Ogasawara (4), and the remaining 112 by none of these laws ([MLIT](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001477518.pdf)). Under the 1953 act, the national government designates areas and prefectures draw up island development plans. In the 2020 census, the 38 designated islands of Okinawa had 126,103 people ([Okinawa Prefecture](https://www.pref.okinawa.jp/_res/projects/default_project/_page_/001/038/825/01.chapter1.r8.pdf)), the eight Amami islands 104,281 and the four Ogasawara islands 2,929 ([MLIT](https://www.mlit.go.jp/policy/shingikai/content/002009910.pdf)).
The Inhabited Remote Border Islands Act (2016) defines inhabited remote border island areas as inhabited islands in areas that include an island on the baseline of Japan's territorial sea, and lists in an annex the specified areas where keeping the community going is especially necessary ([Cabinet Office](https://www8.cao.go.jp/ocean/kokkyouritou/hourei/pdf/houritsu_r9_4.pdf)). The specified areas are 15 areas with 71 islands (8 prefectures, 29 municipalities) and had 244,998 people in the 2020 census. Inhabited remote border island areas as a whole are 29 areas with 148 islands ([Cabinet Office](https://www.cao.go.jp/yosan/pdf/r5/03014200_naikakufu_kokai_sankou.pdf)).
An amendment of 15 July 2026 (Act No. 54 of 2026) adds Teuri and Yagishiri (Hokkaido), Tobishima (Yamagata), Awashima (Niigata) and Niijima and Shikinejima (Tokyo) to the specified areas from 1 April 2027, and extends the act to 31 March 2037. The amended annex lists 19 areas with 77 islands (our count from the annex). Karatsu's seven islands are not in the annex before or after the amendment ([Cabinet Office](https://www8.cao.go.jp/ocean/kokkyouritou/hourei/pdf/houritsu_r9_4.pdf)).

| Island population | Islands | Total population | Share of islands | Share of population | Karatsu's islands |
|---|---|---|---|---|---|
| Under 10 | 33 | 170 | 12.9% | 0.1% | - |
| 10–99 | 90 | 3,777 | 35.3% | 1.1% | Matsushima, Mukushima |
| 100–299 | 63 | 11,583 | 24.7% | 3.4% | Kakara, Takashima, Kashiwajima, Ogawa, Madara |
| 300–999 | 31 | 16,157 | 12.2% | 4.8% | - |
| 1,000–9,999 | 29 | 76,154 | 11.4% | 22.5% | - |
| 10,000 or more | 9 | 231,370 | 3.5% | 68.2% | - |
| Total | 255 | 339,211 | 100.0% | 100.0% | 7 islands |

Note: Our calculation from the population of each island (2020 census) in MLIT's list of designated areas (as of 1 April 2026). Rishiri, Shodoshima and Tanegashima, which span two or more municipalities, are counted once, and prefecture subtotal rows are excluded. We checked that the island rows add up to 255 islands and 339,211 people and match all 26 prefecture subtotals. Shares are rounded to one decimal place, so some columns do not add up to exactly 100.0%. Source: [MLIT, list of designated remote island areas](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001886615.pdf)

## The 255 islands by population size

Grouped by 2020 census population, the 255 islands covered by the Remote Islands Development Act include 33 islands with fewer than 10 people, 90 with 10–99, 63 with 100–299, 31 with 300–999, 29 with 1,000–9,999 and 9 with 10,000 or more (our calculation). 217 islands, or 85.1%, have fewer than 1,000 people, and the median island has 107. The nine islands with 10,000 or more people (Sado, Fukue, Tsushima, Tanegashima, Shodoshima, Iki, Nakadori, Dogo and Yakushima) hold 68.2% of the population of the 255 islands ([MLIT](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001886615.pdf)).
All seven of Karatsu's islands have fewer than 300 people. Matsushima (45) and Mukushima (50) fall in the 10–99 group, and Kakara (117), Takashima (187), Kashiwajima (261), Ogawa (263) and Madara (280) in the 100–299 group ([MLIT](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001886615.pdf)).

| Prefecture | Islands | Population (2020) | Area (km²) |
|---|---|---|---|
| Hokkaido | 6 | 9,819 | 416.74 |
| Miyagi | 7 | 594 | 12.59 |
| Yamagata | 1 | 158 | 2.73 |
| Tokyo | 9 | 21,532 | 290.51 |
| Niigata | 2 | 51,845 | 864.50 |
| Ishikawa | 1 | 66 | 0.55 |
| Shizuoka | 1 | 268 | 0.44 |
| Aichi | 3 | 3,430 | 3.44 |
| Mie | 6 | 2,861 | 13.69 |
| Shiga | 1 | 264 | 1.51 |
| Hyogo | 5 | 4,439 | 21.04 |
| Shimane | 4 | 19,122 | 342.62 |
| Okayama | 14 | 1,553 | 22.62 |
| Hiroshima | 13 | 9,398 | 65.17 |
| Yamaguchi | 21 | 2,755 | 64.41 |
| Tokushima | 2 | 193 | 2.09 |
| Kagawa | 24 | 31,510 | 217.56 |
| Ehime | 31 | 11,671 | 90.40 |
| Kochi | 2 | 142 | 11.33 |
| Fukuoka | 8 | 1,738 | 13.34 |
| Saga | 7 | 1,203 | 10.93 |
| Nagasaki | 51 | 113,056 | 1,550.36 |
| Kumamoto | 6 | 2,584 | 20.83 |
| Oita | 7 | 2,950 | 17.55 |
| Miyazaki | 3 | 721 | 5.19 |
| Kagoshima | 20 | 45,339 | 1,251.34 |
| Total (26 prefectures) | 255 | 339,211 | 5,313.48 |

Note: Areas designated under the Remote Islands Development Act as of 1 April 2026. Population from the 2020 census; area from the Japan Islands Centre's 2023 island statistics yearbook (as noted in the document). Karatsu City's plan gives the area of Saga's seven islands as 10.96 km². Islands of Okinawa, Amami and Ogasawara are not included. Source: [MLIT, list of designated remote island areas](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001886615.pdf)

## Islands and population by prefecture

The 255 islands lie in 26 prefectures. Nagasaki has the most, with 51 islands, followed by Ehime (31), Kagawa (24), Yamaguchi (21) and Kagoshima (20). By population, Nagasaki has 113,056 people, Niigata 51,845 and Kagoshima 45,339. Saga has 7 islands with 1,203 people ([MLIT](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001886615.pdf)).

| Year | Designated remote islands | Amami Islands | Ogasawara Islands | Japan |
|---|---|---|---|---|
| 1955 | 980,086 | 205,363 | - | 90,076,594 |
| 1960 | 940,230 | 196,483 | - | 94,301,623 |
| 1965 | 854,001 | 183,471 | - | 99,209,137 |
| 1970 | 753,265 | 164,114 | 782 | 104,665,171 |
| 1975 | 688,029 | 155,879 | 1,507 | 111,939,643 |
| 1980 | 653,764 | 156,074 | 1,879 | 117,060,396 |
| 1985 | 621,031 | 153,062 | 2,303 | 121,048,923 |
| 1990 | 570,017 | 142,834 | 2,361 | 123,611,167 |
| 1995 | 532,299 | 135,791 | 2,809 | 125,570,246 |
| 2000 | 494,676 | 132,315 | 2,824 | 126,925,843 |
| 2005 | 455,266 | 126,483 | 2,723 | 127,767,994 |
| 2010 | 414,532 | 118,773 | 2,785 | 128,057,352 |
| 2015 | 376,229 | 110,147 | 3,022 | 127,094,745 |
| 2020 | 339,280 | 104,281 | 2,929 | 126,146,099 |

Note: People. Calculated by MLIT from census results. Designated remote islands are the 256 islands designated as of 1 April 2025; Amami covers 8 islands and Ogasawara 4. Ogasawara was under US administration until 1968, so there are no figures for 1955 to 1965. The 2020 figure of 339,280 is for 256 islands and differs from the total of the 255 islands designated as of 1 April 2026 (339,211). Source: [MLIT, measures taken for remote islands in FY2025 (report to the National Land Council, 30 June 2026)](https://www.mlit.go.jp/policy/shingikai/content/002009910.pdf)

## Island population over time

The population of the areas covered by the Remote Islands Development Act was 980,086 in 1955, just after the act was passed, and 339,280 in 2020. Over the ten years from 2010 to 2020, the designated islands fell by 18.2%, Amami by 12.2%, depopulated areas by 15.7% and Japan by 1.5%, while Ogasawara grew by 5.2% ([MLIT](https://www.mlit.go.jp/policy/shingikai/content/002009910.pdf)). In 2015, 39% of islanders were 65 or older, against 27% nationally ([MLIT National Spatial Planning and Regional Policy Bureau](https://www.mlit.go.jp/common/001415188.pdf)).
The population of Okinawa's 38 designated islands rose by 0.1%, from 125,940 in 2015 to 126,103 in 2020 ([Okinawa Prefecture](https://www.pref.okinawa.jp/_res/projects/default_project/_page_/001/038/825/01.chapter1.r8.pdf)).

| Item | 2013 | 2023 | Change | Change in Japan |
|---|---|---|---|---|
| Elementary schools | 288 | 267 | −7.3% | −10.7% |
| Elementary pupils | 16,989 | 13,863 | −18.4% | −9.0% |
| Lower secondary schools | 170 | 169 | −0.6% | −6.4% |
| Lower secondary pupils | 9,021 | 7,274 | −19.4% | −9.7% |
| High schools | 37 | 42 | +13.5% | −3.9% |
| High school students | 7,296 | 5,953 | −18.4% | −11.8% |
| All schools | 495 | 478 | −3.4% | −8.5% |
| All pupils and students | 33,306 | 27,090 | −18.7% | −9.9% |

Note: Designated remote islands: the 256 islands designated as of 1 May 2023 and the 254 designated as of 1 May 2013. Schools include national, public and private. Island figures from the Japan Islands Centre's island statistics yearbook; national figures from the Ministry of Education's School Basic Survey; changes calculated by MLIT. Source: [MLIT (report to the National Land Council, 30 June 2026)](https://www.mlit.go.jp/policy/shingikai/content/002009910.pdf)

## Island schools and ferry routes across Japan

On the designated remote islands, elementary schools fell from 288 in 2013 to 267 in 2023 and their pupils from 16,989 to 13,863 (−18.4%). Lower secondary pupils fell from 9,021 to 7,274 (−19.4%). Over the same period, elementary pupils in Japan as a whole fell by 9.0% and lower secondary pupils by 9.7% ([MLIT](https://www.mlit.go.jp/policy/shingikai/content/002009910.pdf)).
As of 1 April 2025, Japan had 272 remote island ferry routes linking the mainland and islands or islands with each other, 127 of them receiving national subsidies. 84 routes, or 30.9%, are in the area of the Kyushu District Transport Bureau ([MLIT Kyushu District Transport Bureau](https://wwwtb.mlit.go.jp/kyushu/content/000369693.pdf)). The ferries to Karatsu's seven islands are listed under "Ferries to the islands" below.

| Item | Value | Source |
|---|---|---|
| Designated remote islands in Saga | The seven Genkai islands (all in Karatsu City) | Saga plan |
| Population of the seven islands | 1,484 (2015) → 1,203 (2020), down 18.9% | Saga plan |
| Share aged 65+ | 54.1% (prefecture average 30.6%) | Saga plan (2020 census) |
| Distance from the mainland | 0.6–8 km | Saga plan |
| Total area | 10.96 km² | Saga and Karatsu plans |

Note: Karatsu City's plan gives the decrease over the same period as 17.6% and the city's share aged 65+ as 29.4%; the documents do not explain the difference. Sources: [Saga Prefecture](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001619211.pdf), [Karatsu City](https://www.city.karatsu.lg.jp/uploaded/attachment/5987.pdf)

## Saga Prefecture's remote islands

Saga Prefecture's Remote Island Development Plan (FY2023–FY2032) covers the seven Genkai islands of Karatsu City. They lie 0.6–8 km off the mainland, 40 km (Takashima) to 60 km (Madara) from central Fukuoka or Saga, and all are within Genkai Quasi-National Park. The plan's goal is to slow the population decline, which was 18.9% from 2015 to 2020 ([Saga Prefecture](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001619211.pdf)).

- Takashima: 187
- Kashiwajima: 261
- Ogawa Island: 263
- Kakara Island: 117
- Matsushima: 45
- Madara Island: 280
- Mukushima: 50

Note: Population of the seven islands (2020 census). Source: [Karatsu City Remote Island Development Plan](https://www.city.karatsu.lg.jp/uploaded/attachment/5987.pdf)

| Island | Area | Population | Households | Aged 65+ |
|---|---|---|---|---|
| Takashima | 0.62 km² | 187 | 98 | 62.0% |
| Kashiwajima | 1.41 km² | 261 | 130 | 64.4% |
| Ogawa Island | 0.92 km² | 263 | 125 | 55.1% |
| Kakara Island | 2.84 km² | 117 | 57 | 51.3% |
| Matsushima | 0.63 km² | 45 | 21 | 28.9% |
| Madara Island | 4.24 km² | 280 | 126 | 43.2% |
| Mukushima | 0.30 km² | 50 | 20 | 54.9% |
| Total | 10.96 km² | 1,203 | 577 | 54.1% (average) |

Note: 2020 census. MLIT's list (areas from the 2023 Remote Island Statistics Yearbook) gives Kashiwajima 1.39 km², Kakara 2.83 km² and a total of 10.93 km². Sources: [Karatsu City (Table 1)](https://www.city.karatsu.lg.jp/uploaded/attachment/5987.pdf), [MLIT](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001886615.pdf)

## Karatsu's seven inhabited islands

In the 2020 census the islands had: Madara 280, Ogawa 263, Kashiwajima 261, Takashima 187, Kakara 117, Mukushima 50 and Matsushima 45 people. The share aged 65+ ranges from 64.4% on Kashiwajima to 28.9% on Matsushima. There is no ferry between the islands, but the city's plan notes that the seven islands run joint community projects and their residents meet ([Karatsu City](https://www.city.karatsu.lg.jp/uploaded/attachment/5987.pdf)).

| Island | Route | Time | Sailings per day (each way) | Adult fare (one way) | Operator |
|---|---|---|---|---|---|
| Takashima | Karatsu (Chiyoda-machi) – Takashima | about 10 min | 6 | JPY 220 | Saga Genkai Fisheries Cooperative |
| Kashiwajima | Minato – Kashiwajima | about 8 min | 7 | JPY 230 | Karatsu Kisen Co. |
| Ogawa Island | Yobuko – Ogawa Island | about 20 min | 4〜5 | JPY 520 | Kawaguchi Kisen |
| Kakara Island | Yobuko – Kakara Island | about 17 min | 4 | JPY 600 | Kakarashima Kisen |
| Matsushima | Yobuko – Matsushima | about 15 min | 3 | JPY 460 | Shinei Co. |
| Madara Island | Yobuko – Nagoya – Madara Island | 50 min (8:10 from Yobuko, 9:00 at Madara; our calculation) | 4 | JPY 1,000 | Yushomaru |
| Mukushima | Hoshika – Mukushima | about 10 min | 3 | JPY 460 | Mukushima Kisen Co. |

Note: Checked on Karatsu City's timetable pages on 27 October 2026. Sailings vary by season and at New Year (Takashima 4 on 1–3 January; Ogawa 4 on weekdays from 1 November to 14 March). Madara goes via Nagoya; the city page gives no journey time, so we calculated it from the timetable. Source: [Karatsu City](https://www.city.karatsu.lg.jp/page/1013.html)

| Route | Funding | Subsidy (JPY) | Passengers |
|---|---|---|---|
| Takashima | prefectural | 58,131,351 | 111,548 |
| Kashiwajima | national | 50,267,395 | 59,760 |
| Ogawa Island | national | 11,448,050 | 54,784 |
| Kakara Island | national | 29,097,936 | 32,733 |
| Matsushima | prefectural | 50,987,677 | 5,373 |
| Madara Island | national | 35,607,420 | 34,593 |
| Mukushima | prefectural | 45,147,644 | 7,968 |
| Total |  | 280,687,473 | 306,759 |

Note: Karatsu City's ferry subsidies. Subsidy periods: national, 1 Oct 2023–30 Sep 2024; prefectural, 1 Oct 2024–30 Sep 2025. Source: [Karatsu City, FY2025 report (p.19)](https://www.city.karatsu.lg.jp/uploaded/attachment/27438.pdf)

## Ferries to the islands

Each island has a regular ferry from the mainland, taking from about 8 minutes (Kashiwajima) to about 20 minutes (Ogawa). Madara is reached from Yobuko via Nagoya; the 8:10 sailing arrives at 9:00 ([Karatsu City](https://www.city.karatsu.lg.jp/page/1013.html)). In FY2025 Karatsu City spent JPY 299,101,473 (settled) on ferry operations. Passengers on the seven routes numbered 306,759, down 11,044 from 317,803; the city attributes this to fewer anglers and other visitors during the summer heat. 96% of planned sailings ran ([Karatsu City](https://www.city.karatsu.lg.jp/uploaded/attachment/27438.pdf)).

| School | FY2023 | FY2024 | FY2030 (projection) |
|---|---|---|---|
| Takashima Elementary | 7 | 10 | 2 |
| Madara Elementary | 11 | 6 | 4 |
| Kakara Elementary | 5 | 8 | 4 |
| Ogawa Elementary | 10 | 7 | 3 |
| Kakara Elementary, Matsushima branch | - | 0 | 0 |
| Irino Elementary, Mukushima branch | - | 0 | 0 |

Note: Number of pupils. FY2023 and FY2024 are actual counts on 1 May; FY2030 is projected from preschool children on 1 May 2024. The document notes that all island schools have combined classes. Lower secondary pupils are not included. Source: [Karatsu City](https://www.city.karatsu.lg.jp/uploaded/attachment/3198.pdf)

| Island (type) | FY2024 | FY2025 |
|---|---|---|
| Takashima (dormitory, pupils only) | 4 | 4 |
| Kakara (with family) | 2 families, 4 | 2 families, 3 |
| Madara (with family) | 1 family, 2 | 2 families, 4 |
| Ogawa (with family) | 2 families, 4 | 2 families, 5 |
| Total | 5 families, 14 | 6 families, 16 |

Note: Island study-abroad run by the Karatsu Seven Islands Revitalization Council. City subsidy in FY2025: JPY 13,467,770, including JPY 7,382,780 for the dormitory on Takashima. Source: [Karatsu City, FY2025 report (p.22)](https://www.city.karatsu.lg.jp/uploaded/attachment/27438.pdf)

## Island schools

On 1 May 2024 the island elementary schools had 10 (Takashima), 8 (Kakara), 7 (Ogawa) and 6 (Madara) pupils, and the Matsushima and Mukushima branch schools had none. The FY2030 projection is 2 to 4 pupils per school ([Karatsu City](https://www.city.karatsu.lg.jp/uploaded/attachment/3198.pdf)). The Mukushima branch reopened in April 2026 with one pupil and one teacher, after 14 years, according to local news ([Saga Television](https://www.sagatv.co.jp/news/archives/2026042323082)). Through the island study-abroad programme, 16 children from outside came to Takashima, Kakara, Madara and Ogawa in FY2025 ([Karatsu City](https://www.city.karatsu.lg.jp/uploaded/attachment/27438.pdf)). At Takashima Elementary, where we ran workshops, there were 13 pupils in June 2026 and 14 in October ([our records](https://karatsu-f-f.com/island-esd.html)).

| Island | Island community projects (JPY) | Fisheries revitalization grant (JPY) |
|---|---|---|
| Takashima | 1,357,000 | 3,111,000 |
| Kashiwajima | 1,467,000 | 4,146,000 |
| Ogawa Island | 2,184,000 | 8,301,000 |
| Kakara Island | 2,111,000 | 2,067,000 |
| Matsushima | 1,277,000 | 1,380,000 |
| Madara Island | 1,842,000 | 6,742,000 |
| Mukushima | 552,000 | 2,421,000 |
| Seven Islands Council | 210,000 | - |
| Total | 11,000,000 | 28,168,000 |

Note: FY2025 settled amounts. Community projects are subsidies to island residents' committees (wildlife damage control, beautification, international exchange, local products and more). The fisheries grant goes to each island's fishing community; with JPY 50,000 of admin costs the programme total was JPY 28,218,000. Source: [Karatsu City, FY2025 report (pp.21, 76)](https://www.city.karatsu.lg.jp/uploaded/attachment/27438.pdf)

## Money Karatsu City spends on the islands

Of Karatsu City's FY2025 spending, island-by-island amounts are given for community projects (JPY 11,000,000 in total) and the fisheries revitalization grant (JPY 28,168,000). The fisheries grant supports seed release, removal of long-spined sea urchins, raising of red sea urchins and trial seaweed farming ([Karatsu City](https://www.city.karatsu.lg.jp/uploaded/attachment/27438.pdf)). Nationally, MLIT's Remote Island Revitalization Grant supports settlement and exchange projects, such as island information and programmes to grow visitor and related populations. It covers up to 1/2 for prefectures and municipalities and up to 1/3 for private groups, paid through local governments ([MLIT](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001738964.pdf)). The Fisheries Agency's remote island fisheries grant has a FY2026 budget of JPY 1,094 million ([Fisheries Agency (posted on the MLIT website)](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001744151.pdf)).

| Fiscal year | Marine litter collected in Japan |
|---|---|
| 2020 | 27,740 t |
| 2021 | 39,007 t |
| 2022 | 54,264 t |
| 2023 | 27,554 t |
| 2024 (provisional) | 39,551 t |

Note: Collected under the national subsidy for regional measures against drifted litter and related programmes. By prefecture in FY2024: Saga 425 t, Fukuoka 461 t, Nagasaki 2,300 t, Kagoshima 6,140 t, Okinawa 5,852 t. FY2024 is provisional. Source: [Cabinet Secretariat](https://www.cas.go.jp/jp/seisaku/kokudo_kyoujinka/kouhou/5kanen-seika/pdf/5kanen077.pdf)

| Island (year) | What we recorded with the schools |
|---|---|
| Ogawa (FY2023) | 23.07 kg of beach litter collected, of which 15.87 kg (about 69%) was plastic; presented by Ogawa Junior High students |
| Kakara (FY2024) | 28 people collected 79.9 kg on 30 May. PET bottles by country: Japan 100, Korea 59, China 56, Malaysia 5, other 6 |
| Madara (FY2025) | On 7 June, two light trucks of bulky waste and 34 bags of litter at Tajiri beach |
| Takashima (FY2026) | 77 bottle caps picked up on 5 June. By country: Japan 45, Korea 13, China 9, other 10 |

Note: Activities with island schools under Saga Prefecture's Plasma LIFE Saga campaign. Methods differ by island, so the rows are not compared directly. Source: [Karatsu Farm&Food, Island ESD](https://karatsu-f-f.com/island-esd.html)

## Marine litter on the islands

Under the Marine Litter Disposal Promotion Act, the national government subsidizes the collection, disposal and prevention of marine litter by prefectures and municipalities, at 9/10 to 7/10, with higher rates for remote islands, depopulated areas and peninsulas ([Ministry of the Environment](https://www.env.go.jp/content/000424624.pdf)). Japan collected 39,551 t of marine litter in FY2024 (provisional), 425 t of it in Saga ([Cabinet Secretariat](https://www.cas.go.jp/jp/seisaku/kokudo_kyoujinka/kouhou/5kanen-seika/pdf/5kanen077.pdf)). Karatsu City's island plan states that ageing and population decline are making beach cleaning and collection on the islands difficult, and that the mainland coast faces the same problem ([Karatsu City](https://www.city.karatsu.lg.jp/uploaded/attachment/5987.pdf)). In our beach cleanups with island schools, bottles and caps from Korea, China and elsewhere were found on both Kakara and Takashima ([Karatsu Farm&Food (NPO)](https://karatsu-f-f.com/island-esd.html)).

## FAQ

### Q1. How many islands does Japan have?

According to MLIT (as of 1 April 2026), Japan consists of 14,125 islands, of which 14,120 are remote islands and 417 are inhabited. 255 inhabited islands are covered by the Remote Islands Development Act.

### Q2. How many people live on Karatsu's islands?

In the 2020 census, 1,203 people in 577 households lived on Takashima, Kashiwajima, Ogawa, Kakara, Matsushima, Madara and Mukushima, down 18.9% from 1,484 in 2015 (Saga Prefecture).

### Q3. How do I get to Karatsu's islands?

All seven islands have regular ferries from the mainland, taking about 8 minutes (Kashiwajima) to about 20 minutes (Ogawa); Madara takes about 50 minutes from Yobuko via Nagoya. There are 3 to 7 sailings a day each way (Karatsu City timetables, checked 27 October 2026).

### Q4. Where does the litter on the island beaches come from?

In our surveys with island schools, PET bottles collected on Kakara were Japan 100, Korea 59, China 56, Malaysia 5 and other 6; bottle caps on Takashima were Japan 45, Korea 13, China 9 and other 10.

### Q5. Can children study on Karatsu's islands?

Yes. In FY2025, 16 children from outside studied on Takashima (dormitory) and on Kakara, Madara and Ogawa (with their families). Karatsu City spent JPY 13,467,770 on the programme.

### Q6. Are Ogasawara, Amami and Okinawa covered by the Remote Islands Development Act?

No. The four Ogasawara islands, the eight Amami islands and the 38 designated islands of Okinawa each have their own law. The Remote Islands Development Act covers the other 255 islands (MLIT, as of 1 April 2026).

### Q7. How many islands have very few people?

Of the 255 islands under the Remote Islands Development Act, 33 had fewer than 10 people and 90 had 10–99 in the 2020 census; 217 in total had fewer than 1,000 (our calculation from MLIT's list of designated areas).

## Sources

| Document | Publisher | Date | URL | Accessed |
|---|---|---|---|---|
| Composition of Japan's islands (as of 1 April 2026) | Ministry of Land, Infrastructure, Transport and Tourism (MLIT) | 2026-04-01 | [https://www.mlit.go.jp/kokudoseisaku/chirit/content/001477518.pdf](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001477518.pdf) | 2026-10-27 |
| List of designated remote island areas (as of 1 April 2026) | MLIT | 2026-04-01 | [https://www.mlit.go.jp/kokudoseisaku/chirit/content/001886615.pdf](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001886615.pdf) | 2026-10-27 |
| Follow-up of remote island development plans | MLIT National Spatial Planning and Regional Policy Bureau | 2021-06 | [https://www.mlit.go.jp/common/001415188.pdf](https://www.mlit.go.jp/common/001415188.pdf) | 2026-10-27 |
| Remote Island Revitalization Grant (overview) | MLIT | - | [https://www.mlit.go.jp/kokudoseisaku/chirit/content/001738964.pdf](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001738964.pdf) | 2026-10-27 |
| Remote Island Fisheries Revitalization Grant (programme sheet) | Fisheries Agency (posted on the MLIT website) | 令和8年度 | [https://www.mlit.go.jp/kokudoseisaku/chirit/content/001744151.pdf](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001744151.pdf) | 2026-10-27 |
| Marine litter countermeasures: subsidy for regional measures against drifted litter | Ministry of the Environment | 令和9年度要求 | [https://www.env.go.jp/content/000424624.pdf](https://www.env.go.jp/content/000424624.pdf) | 2026-10-27 |
| Measures against drifted litter (results of the five-year acceleration measures) | Cabinet Secretariat | - | [https://www.cas.go.jp/jp/seisaku/kokudo_kyoujinka/kouhou/5kanen-seika/pdf/5kanen077.pdf](https://www.cas.go.jp/jp/seisaku/kokudo_kyoujinka/kouhou/5kanen-seika/pdf/5kanen077.pdf) | 2026-10-27 |
| Saga Prefecture Remote Island Development Plan (FY2023–FY2032) | Saga Prefecture | 2023-04 | [https://www.mlit.go.jp/kokudoseisaku/chirit/content/001619211.pdf](https://www.mlit.go.jp/kokudoseisaku/chirit/content/001619211.pdf) | 2026-10-27 |
| Karatsu City Remote Island Development Plan | Karatsu City | 2023-04 | [https://www.city.karatsu.lg.jp/uploaded/attachment/5987.pdf](https://www.city.karatsu.lg.jp/uploaded/attachment/5987.pdf) | 2026-10-27 |
| FY2025 Report on the Results of Major Policies | Karatsu City | 令和7年度 | [https://www.city.karatsu.lg.jp/uploaded/attachment/27438.pdf](https://www.city.karatsu.lg.jp/uploaded/attachment/27438.pdf) | 2026-10-27 |
| Projected number of elementary school pupils in the city | Karatsu City | 令和6年5月1日現在の実数による | [https://www.city.karatsu.lg.jp/uploaded/attachment/3198.pdf](https://www.city.karatsu.lg.jp/uploaded/attachment/3198.pdf) | 2026-10-27 |
| Karatsu City remote island ferry information and timetables | Karatsu City | - | [https://www.city.karatsu.lg.jp/page/1013.html](https://www.city.karatsu.lg.jp/page/1013.html) | 2026-10-27 |
| Mukushima branch school reopens after 14 years (news) | Saga Television | 2026-04-23 | [https://www.sagatv.co.jp/news/archives/2026042323082](https://www.sagatv.co.jp/news/archives/2026042323082) | 2026-10-27 |
| Island ESD: learning from marine debris on four islands off Karatsu | Karatsu Farm&Food (NPO) | 2026 | [https://karatsu-f-f.com/island-esd.html](https://karatsu-f-f.com/island-esd.html) | 2026-10-27 |
| Measures taken for remote islands in FY2025 (National Land Council, remote islands subcommittee, document 2-2) | MLIT | 2026-06-30 | [https://www.mlit.go.jp/policy/shingikai/content/002009910.pdf](https://www.mlit.go.jp/policy/shingikai/content/002009910.pdf) | 2026-10-27 |
| Remote island data (March 2026), chapter 1: designated islands and population | Okinawa Prefecture | 2026-03 | [https://www.pref.okinawa.jp/_res/projects/default_project/_page_/001/038/825/01.chapter1.r8.pdf](https://www.pref.okinawa.jp/_res/projects/default_project/_page_/001/038/825/01.chapter1.r8.pdf) | 2026-10-27 |
| Policy for inhabited remote border islands (FY2023 administrative project review) | Cabinet Office, Secretariat of the Headquarters for Ocean Policy | 2023 | [https://www.cao.go.jp/yosan/pdf/r5/03014200_naikakufu_kokai_sankou.pdf](https://www.cao.go.jp/yosan/pdf/r5/03014200_naikakufu_kokai_sankou.pdf) | 2026-10-27 |
| Inhabited Remote Border Islands Act as amended (in force April 2027) and outline of the amendment | Cabinet Office, Secretariat of the Headquarters for Ocean Policy | Act No. 54 of 2026 | [https://www8.cao.go.jp/ocean/kokkyouritou/hourei/pdf/houritsu_r9_4.pdf](https://www8.cao.go.jp/ocean/kokkyouritou/hourei/pdf/houritsu_r9_4.pdf) | 2026-10-27 |
| Passenger shipping routes (as of 1 April 2025) | MLIT Kyushu District Transport Bureau | 2025-04-01 | [https://wwwtb.mlit.go.jp/kyushu/content/000369693.pdf](https://wwwtb.mlit.go.jp/kyushu/content/000369693.pdf) | 2026-10-27 |

## Not covered on this page

We do not evaluate individual islands, groups or programmes, and we do not use values read from charts or figures we could not confirm in primary documents. Lower secondary pupil numbers (no recent public data found), fish catch (the prefecture and the city give different figures), visitor numbers, nuclear emergency plans, remote island ferry passengers nationwide (MLIT's published figures end in FY2021), marine litter by island nationwide (no national total by island was found) and population by island in Amami are not covered.

## Citing this data, workshops, visits and island exchange

To cite the figures on this page, or to ask about workshops on your island or at your school, visits to the Karatsu islands, or exchange between islands, please see our [Island ESD page](https://karatsu-f-f.com/en/island-esd.html#contact), the [contact page](https://karatsu-f-f.com/en/contact.html) or write to [info@karatsu-f-f.com](mailto:info@karatsu-f-f.com).

## About this page

Created by Hiroaki Kojima (Vice Director, [Karatsu Farm&Food](https://karatsu-f-f.com/en/index.html)) / Contact: [info@karatsu-f-f.com](mailto:info@karatsu-f-f.com) ([contact page](https://karatsu-f-f.com/en/contact.html)) / Published: 27 October 2026 / Markdown: [island-data.md](https://karatsu-f-f.com/en/island-data.md)
This page was made with AI. See [How we use AI](https://karatsu-f-f.com/en/data-bank.html#ai).

## Related

▶ [Karatsu Data Bank](https://karatsu-f-f.com/en/data-bank.html)
▶ [Island ESD: four islands off Karatsu](https://karatsu-f-f.com/en/island-esd.html)
▶ [Population and Migration in Numbers](https://karatsu-f-f.com/en/population-data.html)
▶ [Seaweed Beds and Urchin Barrens in Numbers](https://karatsu-f-f.com/en/seaweed-beds-data.html)
▶ [離島の統計（日本語）](https://karatsu-f-f.com/island-data.html)