Sauna & Bath Subscription "FLEXKEY" Expands to 41 Partner Facilities

OPTIMIST Inc. (Headquarters: Meguro-ku, Tokyo; Representative Director: Shunsuke Matsuyama) is pleased to announce that its subscription service for sauna and bathing facilities during off-peak hours, "FLEXKEY (Flex Key)", will begin partnerships with 14 new facilities in April 2026, expanding the total number of partner facilities to 41. While the service has primarily operated in the Tokyo metropolitan area, partnerships with facilities in the Nagoya area will commence in April, fostering network development across regions. FLEXKEY will continue to collaborate with bathing facilities nationwide, offering users a new option to "make sauna a daily habit" and providing facilities with a new management model to "turn idle time into revenue.". FLEXKEY is a monthly flat-rate subscription service that allows unlimited access to partner sauna, public bath, and super public bath facilities in the Tokyo metropolitan area. Currently, it is in a limited pre-operation phase for Makuake supporters, and new member recruitment is temporarily suspended but scheduled to resume around May. To ensure smooth service provision upon reopening, there may be a limit on the number of new members accepted. Those considering using the service are encouraged to check the official social media accounts below to avoid missing recruitment announcements and the latest information. ・Official Instagram: https://www.instagram.com/flexkey.sauna.spa/

・Official X: https://x.com/flexkey711

【Announcement of New Partner Facilities】 As of April 2026, the following 14 facilities have newly joined FLEXKEY as partner facilities: Yunoisen Sokakenkocenter

Sauna & Capsule Sunflower

Daikokuya

Hirata Onsen

Kamiyukan

Hotokuyu

Hira Onsen

Hakusan Onsen

Hato-no-yu

Asahiyu

Yachiyoyu

Kounoyu

Pokapoka Onsen Shinmoriyamanoyu

Takarayu Natural Hot Spring

【Proposal for Sauna & Bathing Facilities】 Many sauna and bathing facilities face challenges such as: ・Existence of time slots with low customer traffic, such as weekday afternoons or early mornings, despite regular operations.

・Difficulty in understanding the cost-effectiveness of advertising and social media initiatives, leading to costs outweighing benefits.

・Investments in customer acquisition strategies that do not lead to improved profit margins.

FLEXKEY is designed to solve these issues and can be implemented without incurring new costs or operational burdens.

FLEXKEY offers usage slots exclusively during typically low-traffic hours*. Facilities receive a monthly contract fee based on the agreement. *Operation will be in parallel with regular customers, not exclusive use.

This system is expected to yield the following benefits: ・Improved and Stabilized Occupancy Rate: Promotes usage during off-peak hours, enabling revenue expansion.

・Creation of Sales Opportunities: Increased customer traffic leads to ancillary sales such as food, beverages, merchandise, and rentals.

・Zero Implementation Cost: No initial, monthly, or ongoing fees are required, and it can be introduced with the existing operational structure.

Facilities interested in this service are encouraged to contact us via email: Email: info.flexkey@optimist.jp 【What is FLEXKEY】 FLEXKEY addresses the challenge of "low-traffic hours" faced by sauna and bathing facilities, such as weekday afternoons and late nights, by offering a subscription service that allows access only during these times for a flat monthly fee. By utilizing these less crowded "idle hours," users can enjoy high-quality sauna and bathing facilities at a more affordable price, while facilities can effectively leverage their underutilized time, creating a "Win-Win" situation for both users and facilities.

With the concept of "Sauna as a Subscription, from Recreation to Daily Life," FLEXKEY aims to transform saunas from special experiences into everyday wellness habits. Through these efforts, we strive to promote Japanese bathing culture, contribute to the sustainable growth of the entire sauna and bathing industry, and support the realization of people's well-being. 【Other Partner Facilities】 ・PARADISE Mita

・Sugoi Sauna Akasaka

・Sugoi Sauna & Stay Azabu Juban Ekimae

・Lion Sauna Shimbashi

・Shogayusa Kin no Kame

・Sauna Dojo

・Times Spa-Rest

・Saunarium Koenji

・Private & Share Sauna KUUMA

・Manten-no-yu Natural Hot Spring

・Matsumoto-yu

・Myoho-yu

・Egotayu

・Sugamo-yu

・Onkura Sauna Kamakura Isezaki

・Onkura Sauna Kamakura Takasaki

・Tenku no Ajito Marushin Spa

・Spa & Capsule Inn Real Sauna Kinshicho

・Sauna Yokozuna Honkawagoe

・saunabal peoplexpeople

・Fujimiyu

・Yuasobi Hiroba Nikko Nikko Yu

・Asagaya Onsen Tendokusen

・Nishikiyoyu

・Kugahara-yu

・Omori-yu

・Yakushiyu

【Supporting Companies & Media】

Spa Works https://spaworks.jp/

Saunad http://saunad.jp/

Saunacolle! https://www.instagram.com/saunacollection/

Furosauna https://furosauna.com/

Saunassa https://saunassa.net/

Sisu https://kimoty.com/sisu/

MAPPA! https://www.instagram.com/mappa_ad/

Furo Manma https://www.instagram.com/furo_manma/

Specialty Sauna Trading Company https://kimoty.com/

JSA https://sauna-bu-alliance.themedia.jp/

【OPTIMIST Inc.】 FLEXKEY Official Instagram: https://www.instagram.com/flexkey.sauna.spa/ FLEXKEY Official X: https://x.com/flexkey711 FLEXKEY Official Website: https://flexkey.optimist.jp/ OPTIMIST Inc. Official Website: https://www.optimist.jp/ Contact: info.flexkey@optimist.jp