Let me get straight to the conclusion. This was a transcendent experience I can only describe as godlike.
After finishing my morning sauna session at Midori no Kaze Resort Kitayuzawa, I got back in the car and headed to my next destination: Noboribetsu Onsen, Hokkaido's pride and joy, known as the "department store of hot springs."
And what a fitting nickname it is. After doing a little research, I discovered that this area boasts no fewer than nine distinct spring types — sulfur, salt, alum, mirabilite, green alum, iron, acidic, sodium bicarbonate, and radium. There's simply nowhere else in Japan where you can enjoy this many varieties of hot spring in one place. It's nothing short of miraculous.
Of all the options in Noboribetsu Onsen, the one I had set my sights on this time was Noboribetsu Grand Hotel. Here, three of those nine springs — sulfur, salt, and iron — flow freely in source-direct baths. And on top of that, I would get to experience the legendary Oni Sauna, officially known as Hozuki no Yu, which sauna enthusiasts widely regard as one of the most intense saunas around. Soaking in a world-class onsen and then stepping into a top-tier sauna. Just thinking about it made my foot press a little harder on the accelerator.
I arrived at Noboribetsu Grand Hotel at 11:30 a.m. Day-use bathing didn't start until 12:30, so I had about an hour to spare. This is where traveling by car is so convenient. I reclined my seat all the way back and settled in for a nap. I had to fully restore my energy for the fierce battle with the Oni Sauna that lay ahead. With the sound of rain as my background music, I closed my eyes, and before I knew it, I had drifted off into a deep sleep.
I snapped awake and checked the time: 12:28. My internal clock is almost frightening in its precision. After nearly an hour of deep sleep, I felt physically sharp and mentally energized. I stepped out of the car, walked through the hotel's impressive entrance, and checked in. On my way to the main baths, I spotted a handful of other day-use visitors.
When I entered the changing room, I caught a glimpse of the outdoor bath through the window, and I was immediately captivated by its beauty. I had already been impressed by photos of Hozuki no Yu on the hotel's website, but seeing it in person was something else entirely. I wanted to sink into that hot spring, step into that sauna, and breathe in the outdoor air while taking in that view. I couldn't hold back my excitement and hurriedly stripped off my clothes.
As I stepped into the main bath area, the atmosphere was almost sacred — like something out of a Roman temple. A massive circular bath surrounded a stone statue at the center, while along the walls, separate tubs offering source-direct sulfur, salt, and iron springs lined up one after another. Which spring to start with? Having to deliberate over something like that was a first for me.
Since it was cool outside and I wanted to warm up, I started with the salt spring. Known as the "warming water," salt springs are famous for their exceptional heat-retaining properties. As I soaked slowly in the free-flowing bath, my chilled body gradually began to radiate warmth from within.
Next, I lowered myself into the iron spring. Oxidized to a reddish-brown by contact with the air, it carried a metallic scent reminiscent of Arima Onsen. It felt as though I was absorbing the raw energy of the earth directly through my skin.
For the sulfur spring, I saved it for the outdoor bath.
The outdoor bath was simply breathtaking. A waterfall and stream ran through the center of the forest, and I could feel the sound of the cascading water and the flood of negative ions washing over my entire body. Scattered maple leaves created a vivid contrast against the lush green. A wooden deck positioned right in front of the waterfall offered a perfect spot for outdoor relaxation, and just beside it sat a rock-hewn outdoor bath, fed by a constant, milky white flow of sulfur spring water.
I moved outside and eased into the sulfur bath. The distinctive scent of sulfur — like soft-boiled eggs — tickled my nostrils, and the water felt remarkably silky against my skin. As I settled in, my attention drifted to the sound of the waterfall and the stunning scenery spread before me.
Beautiful scenery has a special kind of power. Simply gazing at it calms the mind, lifts the spirits, and gently dissolves negative thoughts. Add a superb hot spring into the mix, and it would take real effort to feel anything but happiness. Honestly, how could anything feel this good? I've soaked in more outdoor baths than I can count, but I was utterly convinced that this was the most pleasurable, most immersive onsen experience of my life.
Having savored the onsen department store to the fullest, it was time to move on to the main event: the sauna.
Noboribetsu Grand Hotel rotates its men's and women's baths daily. One is Hozuki no Yu — where I was now — and the other is Rindo no Yu. The star attraction is undoubtedly Hozuki no Yu, which offers both the spectacular atmosphere I've been describing and what is widely considered a top-tier sauna experience. Since day visitors can only access Hozuki no Yu every other day, I had carefully timed my visit to make sure I'd be here on the right day.
Hozuki no Yu has two saunas: the Oni Sauna and the Seiryu Sauna.
The Oni Sauna is set to a searing 110°C and is located in the outdoor area. Its raw, rugged design evokes the lair of a demon. When the auto-löyly activates, the room becomes an inferno. The Seiryu Sauna, by contrast, runs at around 80°C and carries the scent of Hokkaido-grown vihta — bundles of birch branches — with self-service löyly and self-whisking available.
Both saunas were exactly what I was looking for, but I started with the star of the show: the Oni Sauna.
The moment I stepped inside, an overwhelming wave of heat enveloped my entire body. It was the same sharp, penetrating heat I'd experienced at Sauna Shikiji and Ogaki Sauna. With the high humidity from the auto-löyly, the intensity was relentless. Looking around the room, I noticed the sauna stove appeared to hang from the ceiling in a striking design, the benches were beautifully crafted, and through a window directly ahead I could see the waterfall and garden outside.
At temperatures this extreme, there's no room for idle thought. You simply go blank and endure until your body reaches its limit. Eyes closed, nothing but sweat. This primal act is, somehow, the greatest feeling in the world.
I hit my limit and walked out of the Oni Sauna. Time for the cold plunge.
Noboribetsu Grand Hotel's signature feature is its enormous barrel cold plunge bath, 150 centimeters deep — but unfortunately it was out of order that day, so I used one of the other options instead. I slipped into a wide cold plunge bath next to the barrel, big enough for about ten people. The water temperature felt around 12°C. Absolutely incredible. The water quality was exceptional too. Fed by stream water sourced from the foothills to the northeast of Noboribetsu, flowing in as a continuous source-direct supply, I could feel the softness and invigorating freshness of pure natural water directly on my skin.
After the cold plunge, it was time for the outdoor relaxation I'd been waiting for.
I stretched out in a chair right in front of the beautiful waterfall and garden, taking in nature with every part of my body. The sound of the falls echoed in my ears, and with each deep breath, air rich with negative ions filled my lungs. The rain tapped against my skin at a pleasant, rhythmic pace, amplifying the sense of refreshment. Hokkaido, you've done it again. Noboribetsu Grand Hotel, I'm genuinely in awe.
For my second set, I went to the Seiryu Sauna.
If the Oni Sauna hits you with fierce, intense heat, this one embraces you with gentle, rounded warmth. What impressed me most was the scent inside. The moment I opened the door and stepped in, a truly magnificent birch fragrance greeted me. There were other guests already inside, and I couldn't help but breathe in deeply through my nose, savoring the aroma — and letting out a quiet, involuntary sigh of delight.
The lighting was kept low, and the walls arched from ceiling to back wall using finely worked timber, designed to promote the circulation of heat and steam. This means that when you pour water for löyly, the warmth wraps around from behind. It's an exceptionally well-crafted sauna. The fierce heat of the Oni Sauna is exhilarating in its own right, but personally, the Seiryu Sauna might be more my style.
For my second cold plunge, I used the one inside. There's always a cold plunge bath right where you exit the sauna — the flow is perfectly designed. With multiple cold plunge options available, every single one uses natural stream water in a source-direct flow. If the water is this cold in early June, I can only imagine what it would be like in the dead of winter. Actually, I think I need to come back in winter.
After another round of exquisite outdoor relaxation to reset myself, I added two more sets — one each in the Oni Sauna and the Seiryu Sauna.
Even during my outdoor relaxation, the rain was coming down hard.
My original plan had been to head into the Noboribetsu Onsen resort town for a meal, but venturing out in this rain didn't seem particularly appealing. I decided instead to have lunch at the hotel's café. I ordered a set of beef stew and salad, and lingered over a post-meal coffee. As I ate, I found myself replaying the views from the outdoor bath, the fierce heat and beauty of the Oni Sauna, the fragrance and craftsmanship of the Seiryu Sauna, the shock of the cold plunge, and the transcendent outdoor relaxation — over and over, unable to stop grinning.
And with that, my time at Noboribetsu Grand Hotel came to a close.
Now it was time to get moving toward the evening's activities. I already knew where I was headed. Another of Hokkaido's finest hot spring destinations, and a place where an exceptional sauna awaited. My next stop was Toya-ko Onsen. And the facility where I would enjoy the night's onsen and sauna experience: Toyako Manseikaku Hotel Lakeside Terrace.
From Noboribetsu Onsen to Toya-ko Onsen. The most luxuriously indulgent hot spring-hopping journey of my life was just about to begin.
