Sauna Subscription Service 'FLEXKEY' Adds 4 Partner Facilities from May, Totaling 44 Available Facilities for Daily Use
Sauna and bathing facility subscription service 'FLEXKEY' will expand its partner facilities by 4 from May, making a total of 44 facilities available. New member recruitment will begin soon, and to stabilize the service, a monthly usage limit per facility will be introduced. This aims to benefit both users and facilities.
📋 Article Processing Timeline
- 📰 Published: May 1, 2026 at 03:00
- 🔍 Collected: April 30, 2026 at 18:31
- 🤖 AI Analyzed: April 30, 2026 at 21:27 (2h 55m after Collected)
OPTIMIST Inc. (Headquarters: Meguro-ku, Tokyo; Representative Director: Shunsuke Matsuyama) announces that its subscription service 'FLEXKEY,' which offers access to saunas and bathing facilities during off-peak hours, will add 4 new partner facilities from May 2026, expanding its total number of accessible facilities to 44.
Furthermore, while the service has been operating on a trial basis exclusively for Makuake supporters, we plan to start recruiting new members in the near future. To ensure stable service provision and a sustainable environment for continuous use by a greater number of members, we will change the operation to set a monthly usage limit per facility (Sauna: 4 times/month, Super Sento: 8 times/month, Sento: 12 times/month *Note: usage limit details may change). Please note that this restriction applies to usage at the 'same facility,' so daily service use remains possible by combining multiple facilities. Regarding new member recruitment, the number of recruits may be limited or temporarily suspended depending on service availability. Details will be announced on official SNS and other channels around mid-May 2026.
Official Instagram: https://www.instagram.com/flexkey.sauna.spa/
Official X: https://x.com/flexkey711
[Announcement of New Partner Facilities]
From May 2026, the following 4 facilities will be newly added as FLEXKEY partner facilities:
Sugoi Sauna Gotanda Ekimae
Toshimaen Niwa-no-Yu
Oasis Sauna Astil
Hagi-no-Yu
[Proposal to Sauna and Bathing Facilities]
Many sauna and bathing facilities often face the following challenges:
There are times when customer visits are slow, such as weekday afternoons or early mornings, despite normal operating hours.
Even with advertising and SNS initiatives, the cost-effectiveness is unclear, leading to costs preceding results.
Investment in customer acquisition measures does not easily lead to improved profit margins.
FLEXKEY is designed to solve these challenges and can be introduced without increasing new costs or operational burden.
FLEXKEY asks facilities to provide usage slots only during typically less crowded hours*. Facilities will receive a monthly contract fee according to the agreement.
*This operation coexists with regular customers, not as private bookings.
This mechanism is expected to bring the following benefits:
Improved and stabilized occupancy: Promotes use during off-peak hours, enabling expanded revenue.
Creation of sales opportunities: Increased visits generate secondary sales such as food, merchandise, and rentals.
Zero introduction cost: No initial, monthly, or continuous fees are required, allowing introduction while maintaining existing operational systems.
Interested facilities are encouraged to contact us at:
Email: info.flexkey@optimist.jp
[What is FLEXKEY?]
FLEXKEY focuses on the challenge faced by sauna and bathing facilities regarding 'off-peak hours on weekday afternoons and late nights,' offering a subscription service that allows unlimited use during those times for a fixed monthly fee. By utilizing less crowded 'empty hours,' users can access high-quality sauna and bathing facilities at more affordable prices, and facilities can effectively utilize idle time, realizing a 'Win-Win' for both users and facilities.
Under the concept of 'Sauna from entertainment to daily habit via subscription,' FLEXKEY aims to transform sauna into a routine health practice rather than a special experience. Through these efforts, we contribute to expanding Japanese bathing habits, promoting the sustainable growth of the entire sauna and bathing industry, and supporting people's wellness.
Furthermore, while the service has been operating on a trial basis exclusively for Makuake supporters, we plan to start recruiting new members in the near future. To ensure stable service provision and a sustainable environment for continuous use by a greater number of members, we will change the operation to set a monthly usage limit per facility (Sauna: 4 times/month, Super Sento: 8 times/month, Sento: 12 times/month *Note: usage limit details may change). Please note that this restriction applies to usage at the 'same facility,' so daily service use remains possible by combining multiple facilities. Regarding new member recruitment, the number of recruits may be limited or temporarily suspended depending on service availability. Details will be announced on official SNS and other channels around mid-May 2026.
Official Instagram: https://www.instagram.com/flexkey.sauna.spa/
Official X: https://x.com/flexkey711
[Announcement of New Partner Facilities]
From May 2026, the following 4 facilities will be newly added as FLEXKEY partner facilities:
Sugoi Sauna Gotanda Ekimae
Toshimaen Niwa-no-Yu
Oasis Sauna Astil
Hagi-no-Yu
[Proposal to Sauna and Bathing Facilities]
Many sauna and bathing facilities often face the following challenges:
There are times when customer visits are slow, such as weekday afternoons or early mornings, despite normal operating hours.
Even with advertising and SNS initiatives, the cost-effectiveness is unclear, leading to costs preceding results.
Investment in customer acquisition measures does not easily lead to improved profit margins.
FLEXKEY is designed to solve these challenges and can be introduced without increasing new costs or operational burden.
FLEXKEY asks facilities to provide usage slots only during typically less crowded hours*. Facilities will receive a monthly contract fee according to the agreement.
*This operation coexists with regular customers, not as private bookings.
This mechanism is expected to bring the following benefits:
Improved and stabilized occupancy: Promotes use during off-peak hours, enabling expanded revenue.
Creation of sales opportunities: Increased visits generate secondary sales such as food, merchandise, and rentals.
Zero introduction cost: No initial, monthly, or continuous fees are required, allowing introduction while maintaining existing operational systems.
Interested facilities are encouraged to contact us at:
Email: info.flexkey@optimist.jp
[What is FLEXKEY?]
FLEXKEY focuses on the challenge faced by sauna and bathing facilities regarding 'off-peak hours on weekday afternoons and late nights,' offering a subscription service that allows unlimited use during those times for a fixed monthly fee. By utilizing less crowded 'empty hours,' users can access high-quality sauna and bathing facilities at more affordable prices, and facilities can effectively utilize idle time, realizing a 'Win-Win' for both users and facilities.
Under the concept of 'Sauna from entertainment to daily habit via subscription,' FLEXKEY aims to transform sauna into a routine health practice rather than a special experience. Through these efforts, we contribute to expanding Japanese bathing habits, promoting the sustainable growth of the entire sauna and bathing industry, and supporting people's wellness.