Overview

Retreat to Kose Onsen Hotel, a historic hot spring inn surrounded by forest in a quieter part of Karuizawa. The sound of the Kose River, birdsong, and changing woodland scenery create a relaxing setting away from the busier centre of town.

The property’s history reaches back nearly 150 years to the early Meiji period. Its design brings together the character of a Japanese ryokan and the Western influences that helped shape Karuizawa. You can spend your time soaking in free-flowing spring water, enjoying seasonal Japanese-French cuisine, or relaxing on the wooden deck beside the forest.

Old Karuizawa and its shops are within easy driving distance, while walking routes towards Shiraito Falls and Ryugaeshi Falls begin close to the property. This balance of nature, hot springs, dining, and sightseeing makes Kose Onsen Hotel a rewarding base for a slower Karuizawa stay.

Accommodation

Choose from a Suite Room, Western Twin Room, Standard Japanese Room, or a smaller Japanese Room. Every room looks towards Karuizawa’s trees, allowing you to listen to the nearby stream and watch the forest change through the seasons.

The Suite Room combines a bedroom with a separate tatami room. Large windows bring the woodland scenery into the room, while a spacious wooden deck gives you an inviting place to enjoy the highland air. The bathroom and toilet sit in separate areas.

The Western Twin Room includes two generous beds and a private wooden deck overlooking the surrounding greenery. A large window creates a strong connection with the forest, whether you relax inside or step outside for fresh air. This room includes a unit bathroom.

The Standard Japanese Room was renewed in December 2019. Tatami flooring, a broad window-side seating area, and futon bedding create a traditional place to rest with family or friends. The bathroom and toilet are separate, and you also have a wash and changing area.

The smaller Japanese Room sits farthest from the main entrance, making it a good choice when you value a quieter position. It includes tatami flooring, futon bedding, and a unit bathroom.

Every room has its own bathroom supplied with natural hot spring water, so you can enjoy Kose Onsen privately without leaving your room. Room facilities include a television, shower, Washlet toilet, heating, and hair dryer. Shampoo, conditioner, body soap, towels, a toothbrush set, and yukata are also provided.

Dining

Dinner combines seasonal Shinshu ingredients with French cooking techniques and a Japanese sense of presentation. You can enjoy the colourful courses with chopsticks, making the experience feel refined without becoming overly formal.

The Japanese-French menu pairs carefully selected local produce and seasonal ingredients with rice and soup. The Standard Course follows the chef’s changing menu and introduces the flavours of Karuizawa and Nagano throughout the year.

The upgraded course adds Nagano-raised beef and further seasonal ingredients chosen by the chef. Wine pairs naturally with the French elements of the meal, while Japanese sake also complements the local flavours.

Additional dishes may be available depending on the season and current ingredients. Dinner and breakfast are served in the dining room, where wide windows overlook the stream and surrounding trees. The generous spacing between tables gives you time to enjoy your meal at an easy pace.

Onsen and Wellness

Kose Onsen Hotel draws water from two private natural sources with temperatures of approximately 52°C and 45°C. The water flows directly from the source without circulation, filtration, or additional heating. Its abundant flow replaces around half of the water in the baths every hour, keeping the bathing water fresh.

The spring is a sodium bicarbonate hot spring known for its smooth feel and skin-softening qualities. A long soak may also help ease tired muscles, joint stiffness, sensitivity to cold, and fatigue after walking around Karuizawa.

The large indoor bath receives a constant flow of spring water that spills naturally from the tub. You can use the indoor bath from 13:00 until 10:00 the following morning. It closes between approximately 10:00 and 13:00 while the water is completely replaced and the bathing area is cleaned.

Two private open-air baths let you soak among the changing forest scenery. Each bath has room for up to four people and can be used without an additional bathing charge. When a bath is available, lock the changing-room door and enjoy it privately for around 40 minutes. You may return again when it is free.

The private open-air baths are available from 13:00 to 23:00 and again from 7:00 to 9:00. Their sodium bicarbonate water is classified as hypotonic, weakly alkaline, and high temperature.

You can also enjoy natural hot spring water in the private bathroom inside every room, giving you another bathing option at any time during your stay.

Guests with Tattoos

You can enjoy the natural hot spring if you have tattoos by using the hot spring bath inside your room or one of the two lockable private open-air baths. These private bathing options are reserved only for you and the people staying with you.

Facilities

The lounge lobby and wooden deck provide comfortable places to pause between meals and baths. Drinks are available in the lounge, while the deck looks towards the stream and forest. During winter, a wood-burning stove warms the lobby as snow covers the landscape outside.

Dinner and breakfast are served in the spacious dining room beside the stream. Large windows frame the woodland scenery, allowing you to enjoy the natural setting throughout your meal.

Free Wi-Fi is available across the property. Free outdoor parking is also available when you arrive by car.

Activities

Step directly onto the Shinanoji Nature Trail, which follows the Shiraito Highland Way through the forest. From this route, you can explore the woodland around Kose and continue towards Ryugaeshi Falls or Shiraito Falls.

Shiraito Falls spreads across a curved rock wall in fine white streams, while Ryugaeshi Falls offers a quieter forest setting. The surrounding walking routes let you experience Karuizawa’s fresh greenery, autumn leaves, and crisp mountain air at close range.

For shopping and cafés, visit Old Karuizawa Ginza, Harunire Terrace, or Karuizawa Prince Shopping Plaza. Seasonal evening attractions include winter illuminations around Shiraito Falls, the Hoshino area, and Karuizawa Kogen Church.

After exploring, you can return to the forest, soak in the hot spring, and enjoy Japanese-French dining beside the stream.

Additional Features

Standard check-in begins at 13:00, and check-out is by 10:00, although times may differ between accommodation plans.

You can reach the property by local bus from Karuizawa Station and leave the bus at Kose Onsen, followed by a short walk. When driving from the direction of Old Karuizawa, the property sits near the entrance to the Shiraito Highland Way.

Your stay brings together private-source hot spring water, in-room hot spring baths, two private open-air baths, a large indoor bath, seasonal Japanese-French dining, forest views, free Wi-Fi, and complimentary parking.