Japan sits on one of the most geothermally active landmasses on earth, and the numbers show it: roughly 27,000 hot spring sources scattered across all 47 prefectures. This page collects the figures travelers and writers actually need — total source counts, rankings by prefecture, the country's most popular onsen town, and the definition that decides what even counts as an onsen — each with a source and an as-of date so you can cite them with confidence.
Quick Answer
Japan has approximately 27,000 hot spring sources (令和6年度 / FY2024: about 27,899; source: Ministry of the Environment). For raw source count, Oita Prefecture ranks #1 with 5,094 sources (as of March 2025; source: Oita Prefecture, on the Ministry's counting basis). But there is no single "#1 onsen prefecture" — it depends on what you measure: Oita leads in hot spring sources, Shizuoka leads in onsen lodging facilities, and Hokkaido leads in total overnight onsen guests per year. Three different metrics, three different prefectures. By popularity, Kusatsu Onsen in Gunma is the most consistently top-ranked hot spring town in the "repeat-visit" rankings, holding #1 in the "Nippon no Onsen 100-sen" expert survey for 23 straight years and #1 in Jalan's "most want to revisit" onsen ranking for 2025 and 2026 (Jalan's separate "want to visit once" ranking is led by Yufuin). For the traveler, the practical takeaway is simpler still: a hot spring is rarely far away, and every region has its own character.
Cite this page: Tabilane. "Japan Onsen Statistics: Hot Springs by the Numbers (2026)." tabilane.com. https://tabilane.com/japan-onsen-statistics
Onsen in Japan: the big picture
The headline figures come from the Ministry of the Environment, which compiles national hot spring usage statistics (温泉利用状況) each year — the most authoritative national snapshot. A few terms get mixed up constantly, so the table separates them: a hot spring source (源泉) is an individual point where water emerges; an onsen area (温泉地) is a town or district built around one or more sources. They are counted differently and produce very different totals.
| Metric | Figure | As-of | Source |
|---|---|---|---|
| Total hot spring sources nationwide | approximately 27,000 (FY2024: about 27,899) | FY2024 (令和6年度) | Ministry of the Environment, "Hot Spring Usage Statistics" |
| Onsen areas / towns nationwide | 2,839 (down 18 from the prior year) | FY2024 | Kankō Keizai Shimbun (Ministry of the Environment data) |
| Prefecture with the most onsen areas | Hokkaido | FY2024 | Ministry of the Environment |
| What legally counts as an onsen | 25°C at emergence or one of 19 specified components above a set level | 1948 Hot Spring Law | Ministry of the Environment, "Definition of Onsen" |
What this means on the ground: with around 27,000 sources feeding nearly 3,000 onsen areas, a hot spring bath is within reach almost anywhere in the country, from major cities to remote mountain valleys.
The historic ryokan streetscape of Ginzan Onsen, Yamagata. Japan's roughly 27,000 hot spring sources feed nearly 3,000 onsen areas nationwide. (Image: Sakaori via Wikimedia Commons, CC BY-SA 4.0.)
Hot spring sources by prefecture
For raw source count — the number of individual points where hot water emerges — Kyushu dominates the top of the table. Oita Prefecture, home to Beppu and Yufuin, sits comfortably in first place; Kagoshima, with Kirishima and the Sakurajima area, holds second. Because the prefectures publish on slightly different dates, the counts below carry individual as-of notes rather than a single shared one.
| Rank | Prefecture | Hot spring sources | As-of | Source |
|---|---|---|---|---|
| 1 | Oita | 5,094 | March 2025 (令和7年3月末) | Oita Prefecture (Ministry of the Environment basis) |
| 2 | Kagoshima | approximately 2,735 | March 2025 (令和7年3月末) | Oita Prefecture national comparison (Ministry of the Environment basis) |
| 3 | Hokkaido | approximately 2,249 | FY2024 (令和6年度) | Ministry of the Environment (via Hokkaido Onsen Association) |
| 4 | Shizuoka | approximately 2,206 | March 2023 (令和5年3月末) | Ministry of the Environment (Shizuoka Prefecture, on the Ministry's counting basis) |
A few notes on basis, which matter if you reproduce these numbers:
- Oita's 5,094 is the prefecture's published figure as of March 2025 (令和7年3月末), on the Ministry of the Environment's counting basis. Earlier vintages show 5,086 (March 2024) and 5,090 (March 2023); we use the most recent published value and flag the year.
- Kagoshima's 2,735 is the figure in Oita Prefecture's published national comparison as of March 2025 (令和7年3月末) — the same vintage as Oita's, on the Ministry of the Environment's counting basis; we mark it approximately pending the standalone Ministry PDF, but the #2 rank is firm.
- Hokkaido holds third place by source count (approximately 2,249, FY2024), even though it leads the country in onsen areas — a reminder that "most sources" and "most onsen towns" are not the same ranking.
- Two of the top four prefectures (Oita and Kagoshima) are in Kyushu, which is why the island is often called Japan's onsen heartland.
The "#1 onsen prefecture" depends how you measure
This is the figure most people want and the one most often reported wrong. There is no single "top onsen prefecture," because the answer changes completely depending on which metric you choose. Three common metrics each crown a different prefecture, and each counts a different thing.
| Metric (what it counts) | #1 Prefecture | Figure | As-of | Source |
|---|---|---|---|---|
| Hot spring sources (individual emergence points) | Oita | 5,094 sources | March 2025 (令和7年3月末) | Oita Prefecture (Ministry of the Environment basis) |
| Onsen lodging facilities (hotels & inns with hot spring baths) | Shizuoka | #1 nationwide (its source count ranks only 4th) | March 2024 (令和6年3月末) | Shizuoka Prefecture (Ministry of the Environment data) |
| Total overnight onsen guests per year (person-nights) | Hokkaido | approximately 12.3 million (Shizuoka 2nd ≈ 11 million; Nagano 3rd) | FY2022 (令和4年度); ranking stable year to year | Ministry of the Environment "Hot Spring Usage Statistics" / uub.jp (Ministry basis) / Japan Spa Association |
Read the table this way: Oita has the most places where hot water comes out of the ground; Shizuoka has the most inns and hotels you can actually stay at with an onsen bath (despite ranking only 4th in raw sources); and Hokkaido draws the most overnight guests to its onsen over a full year. These are three genuinely different questions, so a headline like "Prefecture X is Japan's #1 onsen prefecture" is only true once you specify the metric. We do not combine them into a single "overall winner," because the counting bases — sources, facilities, and person-nights — measure entirely different things.
An open-air rotenburo at Nigorigo Onsen. Whether a prefecture "leads" in onsen depends on whether you count sources, lodgings, or overnight guests. (Image: Alpsdake via Wikimedia Commons, CC BY-SA 4.0.)
Onsen towns vs hot spring sources
The single most common error in onsen reporting is treating "hot spring sources" and "onsen areas" as the same number. They are not, and conflating them is how a writer ends up claiming Japan has either far too many or far too few hot springs.
- A hot spring source (源泉) is one individual point of emergence — a well, a spring, a borehole. Japan has roughly 27,000 of these.
- An onsen area (温泉地) is a town, village, or district organized around one or more sources — think of a place name like Kusatsu, Beppu, or Hakone. Japan has 2,839 of these (FY2024; source: Ministry of the Environment data via Kankō Keizai Shimbun).
The prefecture with the most onsen areas is Hokkaido, which is a different ranking from the source-count table above (where Hokkaido is third) and the lodging table (where Shizuoka leads). Keeping these three nouns straight — sources, areas, lodgings — is the whole methodology, and it is why this page is safe to quote: each number is tied to exactly one definition.
Japan's most popular onsen towns
"Most popular" is the softest figure on this page, because popularity is measured differently by each survey — reader polls, booking volume, or expert panels. Where the rankings strongly agree, the result is dependable; where they don't, we say so.
| Rank | Onsen town | Prefecture | Basis | Source |
|---|---|---|---|---|
| 1 | Kusatsu Onsen | Gunma | #1 in "Nippon no Onsen 100-sen" for 23 consecutive years; #1 in Jalan's "most want to revisit" ranking, 2025 & 2026 | Kankō Keizai Shimbun / Jalan / Nippon.com |
Kusatsu is the one town the major rankings consistently agree on. Its "yubatake" (hot water field) in the town center, where mineral-rich water is cooled in long wooden channels, is among the most photographed onsen scenes in Japan, and its sustained #1 finish in the long-running "Nippon no Onsen 100-sen" expert ranking is the strongest single popularity signal available. Below the top spot, rankings diverge — places like Beppu, Hakone, Yufuin, Kinosaki, and Gero rotate through the upper tiers depending on the survey — so we list only the figure that multiple independent rankings confirm rather than inventing a precise ordering.
Note on "popularity": each ranking uses a different basis (expert votes, reader polls, or booking data), so a town's exact position varies by survey. Kusatsu holds #1 in the two "repeat-visit" rankings — the expert "Nippon no Onsen 100-sen" (23 years running) and Jalan's "most want to revisit" list (2026, third year running) — whereas Jalan's separate "want to visit once" (aspirational) ranking is led by Yufuin, with Kusatsu 3rd. We cite only the rankings where Kusatsu's #1 is consistent.
How "onsen" is defined
The reason Japan can report so many sources comes down to the legal definition, which is broader than "naturally hot water." Under the Hot Spring Law of 1948 (温泉法), water qualifies as an onsen if, at the point of emergence, it meets either of two conditions:
- It is 25°C or warmer, or
- It contains at least one of 19 specified components (such as dissolved minerals, metabolic gases, or radon) at or above a defined concentration.
(Source: Ministry of the Environment, "Definition of Onsen.")
This is why the source count is so large: a spring does not have to be hot to be legally an onsen. Water that emerges below 25°C still qualifies if its mineral content clears the threshold — it is then heated for bathing. Knowing this resolves a common point of confusion for visitors: not every onsen is naturally piping hot at the source, and that is entirely normal and legal.
Why the world is fascinated by onsen
The numbers explain the footprint, but they don't quite capture why "Japanese onsen" routinely tops travelers' wish lists, or why the bathing tradition has become one of the country's signature experiences. The appeal is that something this geologically ordinary — heated groundwater — became a refined cultural ritual: the slow undressing, the careful washing before you enter, the long quiet soak with a mountain or a snowfield in view, the slightly dazed walk back to a tatami room afterward.
That tradition is exactly what the figures above describe from the outside. 27,000 sources is not just a count; it is the reason a traveler can be in almost any corner of Japan and still end the day in mineral water that has been used the same way for centuries. New to onsen? Our beginner's guide to onsen covers etiquette, the tattoo question, and exactly how to bathe — the how-to that this data page deliberately leaves to it.
Sources & methodology
Every figure on this page is sourced below with its as-of date and counting basis. Source counts and rankings are perishable; we re-check them against these primary sources at least annually and update the "as-of" dates.
- National source total (~27,000; FY2024 ≈ 27,899): Ministry of the Environment — Hot Spring Usage Statistics (温泉利用状況). The national total has been stable and gently declining in recent years (FY2022 ≈ 27,932 → FY2023 ≈ 27,920 → FY2024 ≈ 27,899). Re-checked against the latest published Ministry PDF (令和6年度, data as of March 2025).
- Onsen areas (2,839; Hokkaido #1 by area count): Ministry of the Environment data, reported via Kankō Keizai Shimbun. Counts areas/towns, not sources — a separate metric.
- Source count #1 (Oita, 5,094, March 2025): Oita Prefecture — hot spring data (温泉データ), on the Ministry of the Environment's counting basis (令和7年3月末: 源泉総数 5,094, national #1). Earlier vintages show 5,086 (March 2024) and 5,090 (March 2023); we use the latest published value and flag the year.
- Source count top four (Oita 5,094 > Kagoshima ≈ 2,735 > Hokkaido ≈ 2,249 > Shizuoka ≈ 2,206): Ministry of the Environment / Oita Prefecture / Shizuoka Prefecture / Hokkaido Onsen Association (all on the Ministry of the Environment's 源泉総数 counting basis). Oita's 5,094 and Kagoshima's 2,735 are both as of March 2025 (令和7年3月末), taken from Oita Prefecture's published national comparison so the top two share a vintage; Shizuoka's 2,206 is the Ministry-basis source total, March 2023, not the narrower active-well count sometimes quoted. Ranks are firm; Hokkaido (≈2,249, FY2024) and Shizuoka (≈2,206, March 2023) are within ~50 sources of each other, so the #3/#4 order is sensitive to the measurement year.
- Lodging facilities #1 (Shizuoka): Shizuoka Prefecture (Ministry of the Environment data), March 2024. Shizuoka leads in onsen lodging facilities while ranking only 4th in raw source count — a deliberate contrast, since the two metrics count different things.
- Overnight onsen guests #1 (Hokkaido ≈ 12.3 million person-nights, FY2022; Shizuoka 2nd ≈ 11 million; Nagano 3rd): Ministry of the Environment — Hot Spring Usage Statistics (温泉利用状況) (令和4年度) / uub.jp (Ministry-basis ranking) / Japan Spa Association. The top three ranks (Hokkaido > Shizuoka > Nagano) are stable year to year on the Ministry's person-nights basis. Hokkaido's FY2022 figure (≈12.3 million) is the Ministry's current-year value; Shizuoka's and Nagano's absolute counts are of the order of 11 million and 8 million respectively (ranking firm, exact figures approximate), so we lead with the order rather than implying a precise same-year count for every prefecture.
- Most popular onsen town (Kusatsu): "Nippon no Onsen 100-sen" (23 consecutive years at #1, via Kankō Keizai Shimbun) and Jalan's "most want to revisit" onsen ranking 2025 & 2026 (#1, three years running). Jalan runs a separate "want to visit once / aspirational" ranking led by Yufuin (Kusatsu 3rd in 2026) — a different metric, which is why we name the specific Jalan list rather than say "Jalan #1" unqualified. Cross-referenced via Nippon.com.
- Definition of onsen (25°C or 19 components; Hot Spring Law 1948): Ministry of the Environment, "Definition of Onsen."
Methodology note: the central discipline of this page is keeping four different counts apart — hot spring sources (~27,000), onsen areas (2,839), onsen lodging facilities (Shizuoka #1), and overnight onsen guests / person-nights (Hokkaido #1). Because these measure entirely different things, we never combine them into a single "overall #1 onsen prefecture." Where a figure is approximate pending the current-year Ministry PDF, it is marked "approximately" rather than stated as exact.
Image credits: Cover image — the yubatake at Kusatsu Onsen, by Aspere (CC0). In-text images are credited in their captions. All images via Wikimedia Commons.
Steam billows over the cobalt-blue Umi Jigoku ("Sea Hell") in Beppu, Oita — the prefecture with Japan's highest hot spring source count (5,094, as of March 2025). (Image: Bpcon98 via Wikimedia Commons, CC0.)
Frequently Asked Questions
How many onsen (hot springs) are in Japan?
Japan has approximately 27,000 hot spring sources (FY2024: about 27,899), according to the Ministry of the Environment. Those sources feed 2,839 onsen areas (towns and districts) nationwide. The two figures count different things — individual emergence points versus organized onsen towns — so they should not be used interchangeably.
Which prefecture has the most onsen?
It depends on what you measure. By hot spring source count, Oita Prefecture ranks #1 with 5,094 sources (March 2025). By onsen lodging facilities, Shizuoka leads (even though its source count ranks only 4th). By total overnight onsen guests per year, Hokkaido leads with about 12.3 million person-nights (FY2022). Three metrics, three different #1 prefectures.
What is the most popular onsen town in Japan?
Kusatsu Onsen in Gunma Prefecture is the most consistently top-ranked in the "repeat-visit" rankings, holding #1 in the long-running "Nippon no Onsen 100-sen" expert survey for 23 consecutive years and #1 in Jalan's "most want to revisit" onsen ranking for 2025 and 2026. (Jalan's separate "want to visit once" ranking is instead led by Yufuin, with Kusatsu 3rd — popularity depends on whether you measure repeat or first-time intent.) Below the top spot, rankings vary by survey, with towns like Beppu, Hakone, and Yufuin rotating through the upper tiers.
What legally counts as an onsen in Japan?
Under the Hot Spring Law of 1948, water qualifies as an onsen if, at the point it emerges, it is either 25°C or warmer, or contains at least one of 19 specified components (such as dissolved minerals or radon) above a set level. This is why a spring does not have to be naturally hot to be legally an onsen — and why Japan's source count is so large.
How many onsen areas are there in Japan?
There are 2,839 onsen areas (温泉地) in Japan as of FY2024, down 18 from the prior year, per Ministry of the Environment data. An onsen area is a town or district built around one or more sources — distinct from the roughly 27,000 individual hot spring sources and from the count of onsen lodging facilities. Hokkaido has the most onsen areas of any prefecture.
Where to stay for an onsen trip
The figures point to the destinations; the next step is a room with a bath. Two names anchor this page: Kusatsu, the town that holds #1 in the long-running "repeat-visit" rankings, and Beppu, the hot-spring hub of Oita — the prefecture with Japan's highest source count. Both have deep line-ups of ryokan and onsen hotels across every budget, so it is worth comparing a few before you book.
Disclosure: This post contains affiliate links. If you book through them, we may earn a small commission at no extra cost to you.
Final Thoughts
For a traveler, the practical lesson behind these numbers is simple: with around 27,000 sources spread across every prefecture, a hot spring soak is rarely more than a short detour from wherever you're headed — and each region delivers its own version, from Oita's steaming Kyushu valleys to Hokkaido's snow-rimmed baths. Once the statistics have placed the onsen, the next questions are how to do it right and where to stay. For the etiquette, the tattoo question, and the step-by-step of bathing, start with our beginner's guide to onsen; when you're ready to pick a specific bath, our guide to Takaragawa Onsen in Minakami is a good place to begin. The numbers describe the network; those guides tell you how to use it.
Figures on this page are sourced and dated in the Sources & methodology section above. Source counts and rankings are updated against primary sources at least annually.