I Looked Into Hakone Kowakidani Onsen Mizu no Oto

On this blog, I keep researching not just campsites, but also detour spots like "let's fold up the tent today and stay at a hot spring inn," almost like an ongoing series.

This time, what caught my attention was Hakone Kowakidani Onsen Mizu no Oto. I came across information saying it has two types of hot spring sources and four large communal baths, and I thought that even as an indoor type, I could probably satisfy myself just by going around the large baths—so I decided to look into it.

What Kind of Inn Is Mizu no Oto

Hakone Kowakidani Onsen Mizu no Oto is apparently a hot spring inn operated by Kyoritsu Resort, located in the Kowakidani area of Hakone Town, Ashigarashimo District, Kanagawa Prefecture.
Here's a summary of the basic information I found:

• Check-in: from 3:00 PM (last check-in is apparently 12:00 AM)
• Check-out: by 11:00 AM
• Booking method: available via online booking on the official website, or by phone (there also seems to be a best rate guarantee)
• Parking: there's a paid parking lot on the premises, and starting with reservations made from April 1, 2026 onward, a fee of 1,500 yen per night per vehicle is apparently set to begin. Reservations made before that date seem to remain free

As for accommodation rates, in the course of my research I came across information suggesting prices ranging from around 15,950 to 77,990 yen per person per night, but I couldn't find any specific figures in the main text of the official website's room or pricing pages. Since rates seem to vary quite a bit depending on the plan, it's probably safest to check the latest pricing on the booking page when you actually consider making a reservation.

Komorin

Since I'm a driver who basically never actually drives, I really appreciated that the timing for when parking fees start is clearly stated. If you're going by car, this might be worth double-checking.

Checking Out the Two Hot Spring Sources and Four Large Communal Baths

The biggest feature of this inn does seem to be the four large communal baths using two different hot spring sources. Both are apparently sodium chloride springs, said to be effective for things like neuralgia, muscle pain, and fatigue recovery.

• Suika no Sho (Kowakidani Onsen): apparently renewed in March 2024, consisting of two baths—"Sasa no Yu" (an open-air bath plus two types of indoor baths) and "Hana no Yu" (indoor bath, reclining bath, open-air bath). Available from 2:00 PM to 11:00 AM the next day (with cleaning from 1:00 AM to 2:00 AM), and apparently alternates between men's and women's use
• Suigetsu no Sho (Miyanoshita Onsen): renewed in March 2023, consisting of two baths—"Hoshi no Yu" (an open-air bath plus two types of indoor baths) and "Tsuki no Yu" (open-air bath, indoor bath, seated bath). Available from 3:00 PM to midnight and again from 5:00 AM to noon the next day; this one also seems to alternate between men's and women's use, though the official website didn't specify the exact switch times
• Private open-air baths: three baths in the garden—"Hiiragi no Yu," "Kaede no Yu," and "Wakatake no Yu"—all apparently free and requiring no reservation. It seems you check availability using a lamp on the signboard. Available from 2:00 PM to 1:00 AM and again from 5:00 AM to 11:00 AM the next day, and apparently there are no washing areas

As for saunas and cold plunge baths, I did come across one piece of information saying "each large communal bath has an attached sauna," but I couldn't confirm this in the main text of the official website's hot spring page. If you're considering this inn specifically for the sauna, it might be reassuring to double-check before booking, just in case.

Rooms, Meals, and Spending Time on the Premises

There seem to be several room types across both Suika no Sho and Suigetsu no Sho, including Japanese-Western style rooms and Western-style rooms with private open-air hot spring baths, as well as semi-double rooms geared toward solo travelers—apparently set up so you can choose according to your purpose. For groups of three to four people, bedding for one person appears to be self-service.

For dinner, it seems you can choose between two dining venues at check-in—"Tsutsuji-tei" (a grilled kaiseki course) and "Ashigara" (an Ashigara yuzen kaiseki course). Apparently your preference might not be accommodated if a venue is fully booked. Breakfast is a Japanese set meal, served between 7:00 AM and 9:15 AM. Since July 2025, they've apparently also started offering a low-allergen menu, though it requires advance reservation (by two days prior)—worth keeping in mind.

Apparently there are two suikinkutsu (water chime features) installed on the premises, one at the entrance and one in front of the large communal baths, and there's said to be a small pond in the lobby too. There also seems to be a time in the evening when free "yonaki soba" (late-night noodles) is served, which sounds handy if you check in late and want a small bite. Wi-Fi is apparently partly LAN-based, and the connection method seems to differ depending on the room type, so if that matters to you, it's probably worth checking in advance.

Access and Sightseeing Spots in the Hakone Area

The nearest station is Kowakidani Station on the Hakone Tozan Railway, about a 15-minute walk from the station to the inn. Apparently a dedicated shuttle runs every 10 to 15 minutes between 2:00 PM and 5:00 PM, so if you time it right even when traveling by train, the trip should go smoothly.

By car, the route from the Tokyo direction was described as going via the Tomei Tokyo IC, then the Odawara-Atsugi Road, and exiting at Hakoneguchi IC. During winter (roughly December through March), tire chains or winter tires are apparently recommended, so if you're planning to drive there during that season, it's something to keep in mind.

The official website's nearby sightseeing page introduced spots such as the following (no distances or travel times from the inn were listed):

• Hakone Shrine
• Horai-en (a garden known as a spot famous for azaleas)
• Sengokuhara Highland (a pampas grass field)
• The Hakone Open-Air Museum
• The Pola Museum of Art
• Hakone Kowakien Yunessun
• Lake Ashi
• The Hakone Ropeway

It seems like a location where you could spend one day sightseeing and another day just relaxing at the inn.

Rakuten Mobile Signal Conditions

When I checked this location using the official "My Area Network Simulation" tool, the overall rating came back as "C."

I'll just share this result as-is for the record. If you're planning to use data on the premises, it might be reassuring to check the inn's Wi-Fi setup as well, and to test conditions close to your own usage in advance.

Komorin

Hearing a C rating does make me a little uneasy, but since staying here would probably mean plenty of time away from my phone anyway—soaking in the baths and enjoying meals—personally I'd rather prioritize touring all the large communal baths.

Wrapping Up

To sum it up again, my impression of Hakone Kowakidani Onsen Mizu no Oto is that it's an inn where you can really take your time enjoying the baths, with four large communal baths making use of two hot spring sources, plus three free private open-air baths. There are also multiple options for rooms and dining venues, and small touches like the suikinkutsu and the late-night noodles are intriguing too.

That said, there were some things I couldn't fully confirm just from the main text of the official website, like the specific accommodation rates or whether saunas are actually available, so when you're actually considering a stay, it's probably worth also checking the booking page or calling to ask. The Rakuten Mobile signal conditions came back with a C rating, so if that's a concern, it's probably a good idea to check for yourself using the official tool as well.

This article includes a referral link for Rakuten Mobile's employee referral campaign. For details, please see our Disclaimer & Advertising Notice.

Related Links

• Official Site