Between 2025 and 2026, a quiet shift has been unfolding in guest reviews. The HotelBank Editorial Team used NLP (natural language processing) to classify guest reviews into 79 tags and compared mention frequency across the most recent 3 months (N=309,789) and the trailing 12 months (N=1,551,333). Among all categories, the bathing-related tags “onsen (hot spring)” and “open-air bath” ranked near the top in terms of how much their mention rates rose. Why are mentions of hot springs increasing even amid a relentless heatwave? This article reads the rising-mention trend of bathing-related tags as its axis, decoding the growing preference for onsen and the lodgings that are absorbing that demand, broken down by prefecture.

Bathing-Related Tags Dominated the “Rising Trend”

Let us first sketch the big picture. Lining up the tags whose mention rates changed most between the last 3 months and the trailing 12 months, “onsen” rose +2.48pt versus the prior period and “open-air bath” +1.63pt — the two bathing-related tags broke into the top tier of gains. On top of that, the tag for “water quality / skin-beautifying waters” also grew by +0.68pt, showing that multiple tags around the bathing experience are increasingly talked about together.

What is worth noting is that this rise contrasts with a decline in “location”-related tags. Over the same period, “near the station” fell −1.63pt and “city center” −1.17pt. In other words, the center of gravity of guest interest is shifting, if only slightly, from talk of convenience toward talk of the experience of soaking in the bath. This is because reviews tend to record “what left an impression,” so a rising mention rate suggests that experience is moving closer to the heart of lodging satisfaction. How this rising onsen preference shows up on the price side is explored from the demand-side angle in Will the 2026 Summer Bonus Flow to High-Rate Onsen Ryokan? — ADR Analysis of 5 Hot-Spring Areas.

Source: HotelBank Editorial Team research (NLP analysis of guest reviews; most recent 3 months N=309,789 / trailing 12 months N=1,551,333)

Heat and Hot Springs Are Not Contradictory — Reading It as “Indoor / Nighttime Demand”

“Hot baths in summer” may sound contradictory at first. Yet this rise is, we believe, not at odds with the heatwave. The more daytime outdoor activity is constrained by high temperatures, the more relatively valuable the hours spent back at the inn from evening onward become. An open-air bath is an outdoor experience in which you can soak while feeling the outside air in the cooler hours of night or early morning — one of the few options that lets you avoid the daytime heat while still enjoying “the open air.”

In short, the rising onsen preference can be read as the flip side of summer travel behavior shifting toward a “indoors by day, the bath by night” allocation of time. Indeed, among the lodgings where open-air-bath mentions are conspicuously high, many are properties with ocean- or mountain-view locations that promote nighttime and early-morning bathing. In addition, mentions of family travel (+1.62pt) and of views (+1.49pt) grew over the same period, suggesting that behind it lies a spreading style of stay in which “the time spent at the inn itself becomes the purpose.” For onsen ryokan, this can also be seen as an opportunity to fill the summer off-peak.

That said, this is not a simple causal claim that “onsen sell because it is hot.” Rather, it is more reasonable to read it as: the more the heat narrows daytime options, the more the experiential value of the inn itself comes into question, and within that, “bath experiences” such as the open-air bath and the quality of the water become more memorable for guests. The rising mention rate reflects a change not in the volume of demand but in the “quality” of what guests came to value.

Lodgings with High Open-Air-Bath Mention Rates — Prefecture-by-Prefecture Highlights

So what kinds of lodgings are absorbing this preference? For each prefecture, we extracted the property with the highest mention rate for “open-air bath” (based on 100+ mentions, favorable mentions). It is an indicator of the degree to which the open-air bath is talked about as the centerpiece of the lodging experience.

Source: HotelBank Editorial Team research (NLP analysis of guest reviews; 100+ mentions per property)

At Washin-no-Yado Omori in Akita Prefecture, roughly 47% of reviews touched on the open-air bath — a standout mention rate even nationwide. In Shizuoka, Atami Tsukiemon achieved 36.7% (N=473), combining both a large base of reviews and a high mention rate. It is followed by Minamisanriku Hotel Kanyo in Miyagi (32.4%, N=399), Midori-no-Kaze Resort Kitayuzawa in Hokkaido (31.5%), and Awara Onsen Mimatsu in Fukui (29.8%) — showing that across Tohoku, Hokkaido, and the Izu area, the open-air bath has become the center of how people talk about choosing an inn. On the point that popularity-poll rankings and actual lodging satisfaction do not always align, Kusatsu, Beppu, Hakone: A Thorough Verification of the Gap Between Popular-Onsen Rankings and Actual Satisfaction tests the question against 955,000 reviews.

Source: HotelBank Editorial Team research (NLP analysis of guest reviews)

Talk of “Water Quality” Is Also Rising — Interest in the Quality of the Experience

The way guests talk about the bathing experience does not stop at the open-air bath as a “place.” Over the same period, the tag for “water quality / skin-beautifying waters” also rose by +0.68pt, as more voices evaluate the quality of the water itself. Among the lodgings with high water-quality mentions are long-established properties in hot-spring areas long known for the quality of their waters, such as Suimeikan in Gero Onsen (Gifu), Hotel Kasuien in Ureshino Onsen (Saga), and Hotel Sakurai (Gunma).

This is instructive for onsen ryokan operators. Beyond the open-air bath as a facility, putting the quality of the water and the story of the bathing experience into words and conveying them translates into how readily a property is talked about in reviews — that is, into communicative reach. In other words, the whole experience of “soaking in fine water while feeling the open air” is becoming an axis that supports year-round preference, including the summer. This can be seen as an opportunity for differentiation.

In particular, the characteristics of the water — “skin-beautifying waters,” a “silky, viscous feel” — are hard to convey in photographs, yet they are also elements that guests who have actually bathed readily put into words in reviews. The fact that properties in areas known as skin-beautifying or renowned springs — such as Ureshino Onsen in Saga and Gero Onsen in Gifu — line the upper ranks of water-quality mentions shows that reviews gain depth when regional brand and a property’s own communication mesh. At the same time, even outside well-known hot-spring areas there are lodgings winning mentions by carefully conveying the characteristics of their water, which suggests the upside is broadly distributed.

Source: HotelBank Editorial Team research (NLP analysis of guest reviews; 60+ mentions per property)

A Note on Price — The “Two-Meal” Plan That Underpins Onsen Stays

The value of a stay at an onsen inn is formed inseparably from meals. Price is no more than a reference indicator, but a paired analysis comparing, within the same hotel, the price gap between room-only plans and meal-inclusive plans shows that in Hokkaido — home to many hot-spring areas — two-meal plans carried an average premium of +92.5% (about +¥17,900) over room-only (as of April 2026; room-only average ¥19,300 → two-meal average ¥37,200).

This can be called a reference figure indicating that guests recognize commensurate value in “a night spent at the inn” combining bath and food. Given that many of the lodgings with high open-air-bath mentions are two-meal ryokan or resort types, the rise in talk of the bathing experience can be seen as moving in tandem with the creation of added value across the whole stay. Pricing is not the point we wish to put center stage, but it is fair to say that the more a lodging’s open-air bath and water quality are talked about in reviews, the stronger the foundation it has for promoting the value of the stay.

Conclusion — The “Rising Preference” Onsen Ryokan Should Seize

Review trends reflect that guest interest is shifting, if only slightly, from convenience toward experience. The fact that bathing-related tags rose together over the last 3 months — “onsen” +2.48pt, “open-air bath” +1.63pt, “water quality” +0.68pt — shows that, far from retreating, onsen preference is climbing even amid the heat. Behind it is “indoor / nighttime demand” that shifts the allocation of time toward bathing at night and early morning to avoid the daytime heat.

For onsen ryokan operators, this is a summer customer-acquisition opportunity. By putting the strengths they already hold — the open-air bath and water quality — into words as a nighttime and early-morning bathing experience and communicating them, they can raise how readily they are talked about in reviews. What the top properties in regions such as Akita, Shizuoka, Miyagi, and Hokkaido demonstrate is the fact that the open-air bath can become the center of how people talk about choosing an inn. In seizing this rising preference, crafting the story of the bathing experience looks set to become an ever more effective lever going forward.

Related Articles

• Will the 2026 Summer Bonus Flow to High-Rate Onsen Ryokan? — ADR Analysis of 5 Hot-Spring Areas
• Kusatsu, Beppu, Hakone: A Thorough Verification of the Gap Between Popular-Onsen Rankings and Actual Satisfaction