Nagasaki Shimabara City
A hot spring resort with spectacular views of Ariake Sea and one of Japan's highest-concentration carbonated springs
"HOTEL Seaside Shimabara" is a hot spring resort hotel in Shimabara City, Nagasaki Prefecture. It features two main bath areas, the new building's observatory bath and the main building's yuba-dokoro, each equipped with a dry sauna and a cold plunge bath. Day-use bathing is available from early morning until night. Guests can enjoy one of Japan's highest-concentration carbonated springs and the gentle Shimabara Onsen, along with two separate natural springs, all while taking in the scenery of Ariake Sea. From the open-air bath where you can feel the sea breeze to the tubs where carbon dioxide bubbles cling to your skin, you can enjoy an exceptional time surrounded by the nature of the Water City of Shimabara.

A spacious observatory bath with an extraordinary sense of openness and sweeping views of Ariake Sea and the mountains of Kumamoto across the bay. You can take in the dramatic changing scenery of the sea and sky as time passes. The beauty at sunrise is especially remarkable, and while you immerse yourself in the gentle Shimabara Onsen, you can savor an elegant moment that makes you forget everyday life.

A relaxing bathing area with an open-air bath and a spacious indoor bath. You can enjoy two tubs: the gentle Shimabara Onsen and the rare high-concentration carbonated spring, whose strength ranks among the highest in Japan. While feeling the fresh sea breeze, the fine carbonated bubbles envelop your whole body and gently ease away both mental and physical fatigue.

The dry sauna in the new building's observatory bath and the main building's yuba-dokoro is a quiet place where you can slowly work up a pleasant sweat in a room filled with steady heat. Let your warmed body be embraced by the cold water nearby and move into a crisp, refreshing feeling. If you use the rare high-concentration carbonated spring in place of a cold plunge bath, the special cooldown surrounded by tiny carbonated bubbles will gently unwind your travel fatigue from deep within.
Availability and rates are shown on each booking site.
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[Day-use bathing] Main building yuba-dokoro 12:00-23:00 / New building observatory bath 6:00-12:00, 15:00-23:00 * On the fourth Tuesday of every month, due to maintenance, only one bath area, either the main building or the new building, will be open (6:00-23:00).
Guests with tattoos or body art are not permitted to use the baths.
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JAPAN'S FINEST ONSEN & SAUNA
The Finest Onsen & Sauna in Japan
57 SELECTIONS
Most of what we surveyed never even made it onto this site. This book is a further cut from what did. Our editor bathed in every onsen and sauna in it, and wrote only what they confirmed on the ground.