In 2026, the digits “026” of the Western calendar can be read as “o-fu-ro” (bath in Japanese), and the Japan Anniversary Association has officially registered the year as a once-in-a-millennium “Year of the Bath.” The next time “026” lines up will be in 3026. Against this milestone backdrop, hotels equipped with in-room saunas and lodging facilities promoting on-site saunas as a key feature are appearing one after another. In this article, we aggregate plan price and room name data for over 1,500 sauna-promoting hotels tracked by MetroEngines Research, and quantitatively verify that the average premium rate for in-room sauna rooms is +47%, with a median of +32%. We also confirm that review scores at these properties significantly exceed the national average.

The Sauna Market in 2026: Where the “Year of the Bath” Stands

The “2026 Year of the Bath Project” launched on November 26, 2025 (Good Bath Day) as the first cross-industry initiative spanning bathhouses, hot-spring facilities, and sauna venues, organized by the National Public Bathhouse Sanitation Trade Association, the Japan Sauna and Spa Association, and the Hot-Spring Bathing Promotion Association. It became the first “anniversary year” registered by the Japan Anniversary Association. Approximately 2,000 facilities nationwide are participating, with promotions such as free admission for children every 26th of the month.

This momentum within the bath industry reflects structural change in the sauna market. According to the “2026 Japan Sauna Survey” conducted by the Japan Sauna and Onsen Therapy Research Institute in February 2026, the total population of sauna enthusiasts visiting at least once a year stands at approximately 15 million, roughly flat year on year. However, heavy users who visit four to eight or more times per month grew by +35% YoY (from 1.8 million to about 2.5 million). Mid- and light-tier users have declined slightly, and the market is showing signs of “core-segment densification” alongside light-segment churn — a clear bipolar pattern.

This structure sends a clear signal to the hotel industry. Heavy users seek not just the “totonou” (well-balanced) experience, but authentic sauna equipment, high-quality cold baths, fresh-air bathing environments, and privacy. Premium-priced offerings that maintain satisfaction even at higher rates have crystallized in upper-class propositions such as in-room saunas and dedicated loyly functions. Meanwhile, mid-range business hotels equipped with shared saunas function as a differentiation tactic for the light-to-mid segment.

2026 New Openings: Flagship Sauna-Focused Properties

Among the new hotels scheduled to open in 2026, we highlight properties that explicitly position sauna as a core differentiator. What they share is a design philosophy treating sauna not as a mere amenity but as “the centerpiece of the stay experience.”

Source: Compiled by HotelBank Editorial Team from press releases (FAV LUX Miyazaki opens July 1, 2026)

Of particular note is the concept of “a stay that recovers through sauna and sleep” embraced by FAV LUX Miyazaki (opening July 1, 2026). The shared sauna employs a METOS auto-loyly stove with over 100 years of heritage and bench heaters, complemented by a 90 degrees Celsius sauna room and two chiller-cooled cold baths at different temperatures: 15 degrees Celsius (90 cm deep) and 9 degrees Celsius (60 cm deep). Guests can enjoy fresh-air bathing on a “Totonoi Terrace” overlooking the Oyodo River. The 83 sqm Sauna Suite further offers a 40 sqm private balcony and an in-room private sauna, paired with the “LOX-Fit” hypoxic gym simulating an altitude of 2,500 m and TENTIAL “BAKUNE” recovery wear – proposing a wellness stay integrating sauna, fitness, and sleep.

FAV LUX Miyazaki is the latest property in this brand’s nationwide chain of five sauna hotels (Hida Takayama, Nagasaki, Kagoshima Tenmonkan, Sapporo Susukino, and Miyazaki). All properties feature a Finnish x Morris-style hybrid sauna and two cold baths as standard. At the Kagoshima Tenmonkan property opened in December 2024, “SAUNAGE(R)” – the in-room sauna produced by Mikie Sasano of “Sauna Shikiji,” Japan’s holy ground of saunas – was introduced for the first time at any Japanese hotel. This commitment to the quality of the sauna experience defines the brand’s positioning. Sauna is no longer a standalone amenity but is being redefined as a core element of immersive wellness stays.

-> Hyatt Centric Sapporo Opening – Foreign Brand Expansion in Hokkaido and ADR Trends

Quantifying In-Room Sauna Premium: Average +47%, Median +32%

From booking data tracked by MetroEngines Research, we extracted hotels offering in-room saunas (N=574 properties) and hotels with on-site saunas (N=1,051 properties). We compare average prices for check-ins between May 15-22, 2026 (weekdays after Golden Week).

Source: Compiled by HotelBank Editorial Team from MetroEngines Research (N=530 in-room sauna properties, 936 on-site sauna properties, May 15-22, 2026 check-ins)

Hotels with in-room saunas have an average ADR of ¥69,900, while on-site sauna hotels average ¥31,200 – roughly a 2.2x gap. However, this gap is largely attributable to the fact that in-room sauna offerings are concentrated in luxury ryokans and resorts. To refine the data, we calculated the internal premium rate for 356 properties that offer both sauna and non-sauna rooms within the same hotel.

Source: Compiled by HotelBank Editorial Team from MetroEngines Research (N=356 properties, sauna vs. non-sauna room ADR comparison within the same hotel)

The result is unambiguous. 85.4% of the 356 properties achieved a positive premium for sauna rooms, with an average premium rate of +47.0% and a median of +32.4%. (Note: a separate 38-property analysis that strictly extracted “private sauna” room names yielded a +20.4% premium rate – be mindful that figures vary depending on how the sample is defined.) In monetary terms, this translates to a median uplift of ¥13,400 and an average of ¥23,000. Notably, 11.0% of properties (39 facilities) achieved premiums of 100% or more, demonstrating that in-room saunas function as a clear pricing factor in the upper-class segment.

On the other hand, in 14.3% of properties non-sauna rooms commanded higher prices. In most such cases, sauna-equipped standard rooms coexist with larger suites or higher-floor view rooms without saunas – pricing structures that prioritize floor area or view over sauna alone.

Sauna Properties Show Strong Positive Correlation with Review Scores

What underpins these premium prices is high guest satisfaction. We examine the review score distribution of sauna-promoting hotels using review data collected by MetroEngines Research (limited to properties with 30+ reviews).

Source: Compiled by HotelBank Editorial Team from MetroEngines Research (in-room sauna N=236, on-site sauna N=804, national baseline N=49,913)

The average review score for in-room sauna hotels is 4.11/5.0, with a median of 4.26 – significantly above the national average of 3.42. The share of properties scoring 4.0 or higher reaches 65.7%, meaning roughly two out of three fall into the “premium quality” range. On-site sauna hotels also average a high 3.93/5.0, about +0.5 points above the national average. Sauna-focused properties tend to maintain not only superior facilities but also high overall service quality across hospitality, cleanliness, and dining.

That said, correlation is not causation. Rather than “saunas drive higher ratings,” the more likely relationship is that properties with the resources to invest in experience quality also adopt saunas. Either way, the result is a market-level selection effect – “sauna = high score” – which serves as a useful signal for guests choosing accommodations.

-> Hotel Dining Chosen for Anniversaries | Luxury Hotel Restaurant Review Rankings in Tokyo, Osaka, and Nagoya

Category and Grade Distribution of In-Room Sauna Hotels

Looking at the category and grade distribution of the 236 properties with in-room saunas (30+ reviews), the market’s center of gravity becomes clear.

Source: Compiled by HotelBank Editorial Team from MetroEngines Research (N=236 properties)

By category, ryokans top the list at 118 properties (50.0%), followed by 37 resort hotels, 36 business hotels, 13 city hotels, and 12 cottages. By grade, luxury dominates with 107 properties (45.3%), followed by 50 upper-class and 40 high-grade. In-room saunas are currently most actively adopted as a differentiator at high-end ryokans, while the business hotel segment still has whitespace.

For on-site (shared) saunas, business hotel chains such as Dormy Inn have built a national presence by combining proprietary natural hot springs with sauna offerings, establishing them as a strong mid-tier differentiation tool. In-room and on-site saunas are not competitors but rather complementary positionings targeting different customer segments.

For Readers: Top 10 Highly-Rated, Affordable In-Room Sauna Hotels

Among the 574 properties nationwide offering in-room saunas, we present the top 10 filtered by review score 4.3 or higher, average sauna-room price under ¥60,000, and at least 5 price data points. For property-level analysis by region or full TOP 20 rankings, please also refer to our In-Room Sauna Hotel Market Analysis: Verifying Price Premium Across 38 Properties Nationwide. We also include each hotel’s internal sauna-vs-non-sauna premium rate. Properties showing negative premiums are cases where sauna rooms are positioned as more affordable entry-level plans.

Source: Compiled by HotelBank Editorial Team from MetroEngines Research (average published prices for May 15-22, 2026 check-ins, all-plan average)

Geographically, Hokkaido (2 properties) and Gunma (2 properties) appear multiple times, illustrating that regions with deeply-rooted onsen-and-sauna culture drive cost-performance ratings. Prices range broadly from ¥18,500 to ¥59,800, and the presence of highly-rated sauna rooms even in city and business hotels is welcome news for business travelers.

Market Implications

The implications drawn from this quantitative analysis can be summarized as follows.

First, in-room saunas are an established price-premium driver. The fact that the same hotel can command +47% on average and +32% at the median validates the ROI of such investment. In luxury ryokans in particular, in-room saunas can lift ADR by 100% or more, functioning as a “decisive differentiator.”

Second, on-site saunas are a reliable differentiation tool for mid-tier hotels. While they don’t generate the dramatic premiums that in-room saunas do, they secure a +0.5 review-score signal of quality, which likely contributes to repeat-visit and direct-booking improvements. With the heavy-user core segment expanding, on-site saunas are an effective lever to compensate for less-than-ideal locations.

Third, the market still has whitespace in “in-room saunas in the business hotel segment.” While in-room sauna adoption clusters in luxury ryokans, only 36 business hotels and 13 city hotels offer them. Cases like Nice Inn Hotel Maihama Tokyo Bay PREMIERE and La Jolie Motomachi hint at how to tap a new “business travel x wellness” demand layer.

-> The Reality of Business Hotel Price Surges – National ADR Analysis and Top 10 Cost-Performance Prefectures for Business Travel

The 2026 “Year of the Bath” is not just an industry marketing campaign; it marks a structural maturation of the sauna and bathing market and symbolizes the establishment of in-room saunas. The +32% premium revealed by the data speaks to the seriousness of this market.

References: “2026 Year of the Bath Project” Official Site / Japan Sauna and Onsen Therapy Research Institute