Private Sauna Villa in Gunma | THE FOREST SAUNA in the Kitakaruizawa Highlands

THE FOREST SAUNA is a private one-villa rental tucked into the forests of Tsumagoi Village (Kitakaruizawa area), Gunma Prefecture. Up to 5 guests. The sauna, water bath, and outdoor rest deck are entirely yours—no shared spaces, at any hour. Stargaze at midnight or rest with the dawn birdsong; the rhythm of the day is yours to set.

The sauna is a Finnish HARVIA barrel sauna. Heat circulates evenly through the round wooden chamber, and you control the steam and humidity through self-löyly. Through the open window, you watch the forest while you warm up—something you simply cannot do indoors. Up to 4 adults at a time.

The water bath sits on the wooden deck, filled with natural mountain spring water. Soft on the skin, open to the sky, exactly the kind of cooldown the body craves after a long round in the heat.

Infinity chairs on the deck make outdoor rest effortless—forest breeze, dappled sunlight, and the sounds of the woods. It's the part guests talk about most.

For sauna technique and the "totonoi" cycle, see our Barrel Sauna Guide.

Kitakaruizawa & Tsumagoi sit on the northern foothills of Mt. Asama, at 650–1,300m elevation. Summer averages 24–25°C—more than 5°C cooler than Tokyo. That cool highland climate is the single biggest reason this place is worth the drive.

Late spring (May): cherry blossoms and fresh greenery peak from late April to early May. Crisp post-thaw air sharpens the contrast between the sauna and outdoor rest.

Early summer (June): deep greenery, comfortable humidity. Ideal conditions for steady cycles of sauna → water → rest.

Midsummer (July–August): while Tokyo bakes above 30°C, Kitakaruizawa often dips below 20°C in the early morning and evening. You can pass the day without air conditioning. The natural water bath after a sauna round, then resting in an infinity chair under forest shade—that's what summer here is about.

For detailed summer tips, see our Summer Sauna Villa Guide. Other seasons: spring / autumn / winter.

A 59㎡ whole-villa rental for up to 5 guests. Living/dining/kitchen + bedroom, suitable for groups and families.

Key facilities: HARVIA barrel sauna / Natural water bath (deck) / Infinity chairs / 80-inch projector / Full kitchen (IH, fridge, microwave, rice cooker) / Washer / Wi-Fi / Heating / BBQ grill with charcoal (free).

Amenities: Bath & face towels / Toothbrush / Shampoo, conditioner, body soap / Hair dryer.

Bring insect repellent in summer. BBQ ingredients, your preferred coffee, and seasonings should be brought separately.

For full facility details, see the Barrel Sauna Villa Stay Guide.

Mainly accessed by car. From Tokyo: Kan-Etsu → Joshinetsu Expressway → Usui-Karuizawa IC → Route 146 for ~60 minutes (about 2.5 hours total from Tokyo Station).

Train + taxi: Karuizawa Station → Naka-Karuizawa → taxi (40 min), or Manza-Kazawaguchi Station → taxi (20 min).

Regular tires fine May–October; studless tires required Nov–April. See the Access Guide for details.

Booking is via Airbnb. Rates vary by season and party size—please check the Airbnb calendar for availability. Facility details are on the villa page.