This sprawling outdoor hot spring resort in Hakone combines traditional volcanic onsen bathing with themed baths including sake, wine, and coffee pools. Multiple indoor and outdoor pools across different temperature ranges surrounded by mountain scenery.
Hakone Kowaki-en Yunessun is a large-scale hot spring resort at 1297 Ninotaira, Hakone, Kanagawa Prefecture, combining the therapeutic benefits of Hakone's volcanic onsen waters with a series of themed novelty baths that have made it one of the most visited bathing destinations in the Kanto region. The resort sits in Hakone's forested mountains approximately 90 minutes from central Tokyo and operates across two interconnected zones: Yunessun, the swimwear-permitted main resort, and Mori no Yu, the traditional gender-separated naked bathing area.
The volcanic spring waters sourced from Hakone's geothermal system are naturally rich in sodium chloride and sulfur compounds, associated in traditional Japanese balneology with benefits for skin conditions, muscle recovery, and circulation. Water temperatures across the resort range from cool plunge pools to hot thermal baths of approximately 42 degrees Celsius, allowing visitors to cycle between temperatures in the manner of traditional Japanese bathing culture.
Yunessun's distinctive draws are its themed baths: a large outdoor sake pool filled with rice wine-infused water, a wine bath using red wine concentrate, a green tea bath, and a coffee bath. These pools are set against genuine mountain scenery, and the outdoor baths offer partial views towards Mount Fuji on clear days. Waterslides add a family leisure dimension to the site.
Mori no Yu, the traditional section, operates as a conventional rotemburo (outdoor onsen) and indoor bath facility with higher water temperatures and a more tranquil atmosphere suited to adults seeking therapeutic bathing. Separate facilities for men and women are maintained here, and swimwear is not permitted in this zone.
Admission includes access to all pools within the chosen zone, with combination tickets available for those wishing to access both areas. Towel and yukata rental is available at the entrance. Multiple on-site restaurants serve Japanese meals and light refreshments throughout the day.
Treatments
- Volcanic spring thermal bathing
- Sake bath soak
- Red wine bath
- Green tea bath
- Rotemburo outdoor onsen
- Cold plunge pool therapy
Good to know
- Signature
- Outdoor sake bath and wine bath with Fuji mountain views
Highlights
- Outdoor sake bath and wine bath using volcanic spring water infused with Japanese rice wine and red wine
- Genuine Hakone volcanic onsen waters rich in sodium chloride and sulfur compounds
- Separate Mori no Yu section for traditional gender-separated rotemburo bathing without swimwear
- Mountain setting with partial Mount Fuji views on clear days from outdoor pools
- Wide temperature range from cool plunge pools to 42°C thermal baths across multiple pool areas
Tips for visiting
- Bring or rent a swimsuit for the Yunessun themed pools — nudity is only permitted in the separate Mori no Yu section
- Arrive early on weekends and public holidays, as queues form by mid-morning during peak season
- Purchase a combination ticket at the entrance to access both Yunessun and the quieter Mori no Yu
- Towel and locker rental is available at reception for visitors who prefer to travel light
- Avoid the sake and wine baths if you have open cuts or highly sensitive skin, as the acidity can cause mild irritation
- The outdoor pools are at their most scenic on clear winter mornings when Mount Fuji is visible above the treeline
Frequently asked questions
What is the difference between Yunessun and Mori no Yu?
Yunessun is the main swimwear-permitted resort area with themed and novelty baths. Mori no Yu is the traditional section with gender-separated indoor and outdoor baths where swimwear is not worn.
Can children visit Hakone Kowaki-en Yunessun?
Yes, Yunessun is family-friendly and includes waterslides and pools suited to children. Age and height restrictions apply to certain attractions. Mori no Yu is generally recommended for adults.
Is a reservation required?
Walk-in entry is accepted. On busy weekends and during autumn foliage season, queues can be significant and arriving early is strongly advised. Online tickets can save time at the gate.
Are tattoos permitted at the facility?
Yunessun has historically been more permissive toward visible tattoos than traditional onsen, but policy can change. Visitors with tattoos are advised to check the current rules directly before visiting, as individual pool restrictions may apply.
Are there dining facilities on site?
Yes, multiple on-site restaurants serve Japanese cuisine, ramen, and light meals. Visitors can eat between bathing sessions without exiting the facility.