Yesterday, I spent a thorough evening at Shinagawa Sauna until 1 a.m., and now I found myself heading to Saitama Prefecture with a slight heaviness behind my eyes. As always, going to bed late leaves you feeling sluggish even if you manage to get the same number of hours of sleep. In cases like this, there's only one solution: get into a sauna first thing in the morning and shock yourself awake.
Starting today, I'll be staying in Tokorozawa, Saitama. There are a handful of exceptional facilities in Tokorozawa that I've been wanting to visit for a long time. One of them — widely regarded as one of the largest spa resorts in the Kanto region — is Onsen Balcony King & Queen, and that's exactly where I'm headed right now. I transferred to the Seibu Ikebukuro Line at Ikebukuro Station and set my sights on Kotesashi Station. This is my first time ever visiting Tokorozawa, and honestly, if it weren't for sauna travel, I probably would have gone my entire life without setting foot at Kotesashi Station. Sauna keeps adding new destinations — and new experiences — to my life. That's something I find genuinely moving.
From Kotesashi Station, a free shuttle bus runs to the facility, and I hopped right on. When I arrived and stepped inside, I was greeted by a gorgeous interior — an expansive, hall-like space where you can eat and drink to your heart's content. The large bath area is located further in, and even the corridor leading there is adorned with illumination, designed in a way that stirs something inside you just by walking through it.
Full of anticipation, I changed and entered the large bath area. First, I took stock of the layout. The baths are divided into indoor and outdoor sections. Indoors, there's a natural hot spring combined with a carbonated bath, a jet bath, a löyly sauna, a cold plunge sourced directly from the spring at 23°C, a cold water bath at 8°C, and a freezer room at -20°C — more than enough even on its own. On top of that, each bath and sauna is enormous, so even on a busy day you'd never feel cramped. The outdoor section features a herb steam sauna, a massive cold plunge at 18°C, a natural hot spring, a silk bath, pot baths, and a rest area lined with over 20 chairs — a scale that could easily stand alone as a super sento. Without a doubt, this place ranks among the very best I've ever visited.
I rinsed off and eased into the indoor natural hot spring combined with the carbonated bath. Plenty of facilities offer carbonated baths on their own, but it's extremely rare to find one that blends locally sourced natural hot spring water into the mix. Perhaps that's why my body was warm and glowing within just a few minutes of soaking. I headed straight to the 23°C cold plunge to cool down, and since that bath also uses hot spring water, it had a wonderfully soft, refreshing quality. I hadn't even been in the sauna yet — and I was already in a state of totonou.
First up: the main attraction, the Fujisan Lava Löyly Sauna. The sauna stones here are made from actual lava rock from Mt. Fuji, letting you feel the energy of Japan's most iconic mountain. The sauna room is built on 7 tiers and can seat more than 40 people. The steps are tall, and the higher you climb, the more intense the heat becomes. For my first set I sat around the middle as a test run — and even there it was plenty hot, well above 90°C. The top tier has to be pushing past 100°C, so I'll challenge that later.
I settled onto the bench and knew within moments that I was sitting in an exceptional sauna. For starters, the benches are incredibly wide, giving you complete freedom in how you position yourself — you could meditate or even stretch out. The sauna mats are thick and plush, genuinely comfortable. They're also replaced frequently, so you always get a fresh one. I happened to catch a staff member doing a changeover, and watching them lay the mats out carefully into every corner made it clear that this facility takes its sauna mats very seriously. Plenty of places treat mat changes as an afterthought, so seeing this level of care was genuinely impressive. The scent inside the room was wonderful too. A sign on the wall explained that they put great thought into their aromatherapy, rotating through different aromas each day. And the humidity management was outstanding. Sweat was pouring off me within minutes of entering — and that's all down to humidity. Regular löyly keeps the moisture level high, which improves heat conductivity and warms your body efficiently. Even the TV volume was kept very low, a thoughtful gesture for those who want to focus and turn inward. This sauna ticks every box for what a great sauna should be — which is exactly why my explanation of it has gone on so long. It's getting hot in here, so let's head to the cold plunge.
Stepping out of the sauna into the outdoor area, I was greeted by a massive cold plunge at 18°C. Calling it a cold plunge might actually be underselling it — pool might be the better word. You can swim in it, dive under, and leap in from the side: it grants every wish a sauna enthusiast could have. The depth is 2 meters, meaning most people won't be able to touch the bottom. I rinsed off the sweat and plunged in like I was diving into a lake. My whole body was enveloped in cooling relief, and an overwhelming sense of freedom washed over me along with the refreshing sensation. I've never been in a cold plunge this large before. You could search the entire country and probably not find another facility with a cold plunge this massive and this exhilarating.
After climbing out of the cold plunge and settling into a chair in the rest area, the words just came out on their own: "This is incredible! That felt amazing!" I generally restrain myself from making noise in public spaces, but apparently there are exceptions when the pleasure becomes truly overwhelming. The other guests were hollering "Yes!" and "Amazing!" after getting out of the cold plunge too, so I figure it's fine. That's just how good it feels.
In the rest area, I lost consciousness entirely. I had no idea what time it was, but once I came back to myself, I headed in for my second set. This time I tried the Herb Steam Sauna. The room was filled with the scent of natural herbs, and the moment I stepped in I was seized by an urge to take a deep, full breath through my nose — and I did exactly that. The smell was wonderful. And despite being a steam sauna, it runs at 90°C, so it was absolutely brutal. I hit my limit after about five minutes and leapt back into the giant cold plunge.
Onsen Balcony King & Queen is truly outstanding in both its hot springs and saunas, but it was the outdoor section's massive cold plunge that genuinely shocked me — the exhilaration it offers is something special. I ended up completing 5 sets of sauna and cold plunge that day, diving into that enormous cold plunge again and again.
After a deeply satisfying sauna session, it was time to eat. The restaurant area at Onsen Balcony King & Queen is on a scale that rivals a shopping mall food court — if not surpasses it. With over 20 restaurants to choose from, all of them popular spots, you could honestly call it a food theme park as much as a hot spring and sauna destination.
I chose a Japanese restaurant called Sansui Soumoku. I ordered both the ginger pork set meal and the chicken nanban, and I'm pretty sure the staff gave me a look that said, "Just how much are you eating?" — but I finished everything in one go. Every last bit of energy burned in the sauna was fully recharged.
I have plans to meet someone now, so it's time to say goodbye to Onsen Balcony King & Queen — reluctantly. That said, the place I'm staying tonight is also a very well-known sauna in Saitama Prefecture. Located just a few minutes' walk from Tokorozawa Station, it goes by the name Baden Garden.
