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Best spa & onsen in Kosai

πŸ“ ♨️ Kosai

9 places in Kosai, ranked by real Google reviews. Hot springs, spas and wellness. The most reviewed is Akazawa Onsen Day Spa, with 3,758 reviews.

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  1. ⭐1top
    Akazawa Onsen Day Spa

    Akazawa Onsen Day Spa

    ♨️ Itō, Kosai Shizuoka

    4.3
    β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…3.8K reviews
    SaunaSpaPublic Bath
    🎟 Tickets
  2. ⭐2top
    Hanasaki no Yu Hot Spring

    Hanasaki no Yu Hot Spring

    ♨️ Chūō-ku, Kosai Shizuoka

    4.1
    β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…1.7K reviews
    SpaPublic Bath
    🎟 Tickets
  3. ⭐3top
    Sagara Koumare Onsen Kaikan

    Sagara Koumare Onsen Kaikan

    ♨️ Makinohara, Kosai Shizuoka

    4.0
    β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…1.6K reviews
    HotelSpaPublic Bath
    🎟 Tickets
  4. 4no.
    Akazawa Onsen Hotel

    Akazawa Onsen Hotel

    ♨️ Akazawa, Kosai Shizuoka

    4.3
    β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…1.6K reviews
    Resort HotelJapanese InnSauna
    🎟 Tickets
  5. 5no.
    Yunoyu Toyohashi

    Yunoyu Toyohashi

    ♨️ Imureminami, Kosai Shizuoka

    4.0
    β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…1.5K reviews
    SpaPublic BathBeauty Salon
    🎟 Tickets
  6. 6no.
    Hokkawa Onsen

    Hokkawa Onsen

    ♨️ Japan, Kosai Shizuoka

    4.4
    β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…985 reviews
    Spa
    🎟 Tickets
  7. 7no.
    Laforet Ito Onsen Yunoniwa

    Laforet Ito Onsen Yunoniwa

    ♨️ Itō, Kosai Shizuoka

    4.2
    β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…944 reviews
    HotelSpaLodging
    🎟 Tickets
  8. 8no.
    Sumatakyo Onsen open-air bath Bijinzukuri no Yu

    Sumatakyo Onsen open-air bath Bijinzukuri no Yu

    ♨️ Haibara District, Kosai Shizuoka

    4.2
    β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…424 reviews
    Tourist AttractionSpaPublic Bath
    🎟 Tickets
  9. 9no.
    Umegashima Hot Spring

    Umegashima Hot Spring

    ♨️ Aoi Ward, Kosai Shizuoka

    4.1
    β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…β˜…207 reviews
    SpaJapanese InnTourist Attraction
    🎟 Tickets

About spa & onsen in Kosai

How were these places chosen?+

We rank by a score combining the Google rating, the number of reviews and the recent trend β€” not just popularity.

How is the ranking calculated?+

We use a Bayesian score that blends the average rating with the number of reviews, plus a trend signal (new reviews per month). This keeps a place with 5.0 and 10 reviews from beating a classic with 4.3 and thousands.