Hirauchi Kaichu Onsen (Underwater Hot Spring) — Attraction in Yakushima

Don't waste your time going here as any other onsen is much better. 200 yen entrance fee is too much and even if it was free, I would not recommend it to anyone. Visiting this onsen was single-handedly the worst experience of my 5 month stay in Japan.

The rules of the onsen stated that swimsuits are prohibited in the bath so the natural assumption is that you're supposed to be naked as in any other onsen. Once we got undressed people started yelling at us (both locals and foreigners alike) that they feel uncomfortable and we should cover ourselves. We couldn't get an answer to how we should do that despite trying multiple times. We offered to wear our swimsuits but were not allowed to do so, despite some people being in the baths in dresses and other plain clothes. We had no problem being naked outselves until people yelling and shouting us made us feel really uncomfortable and unwelcome.

When we were finally given the go-ahead to join the bath, we started to rinse ourselves like we were supposed to. As any decent person would, we wanted to respect the local culture and started to properly wash ourselves. After 30 seconds we had barely had the time to soak ourselves, when the locals said that we are overdoing it and should already get in the bath. According to them you're not supposed to actually wash yourself but just quickly splash some water on yourself.

The onsen clearly has its own arbitrary rules that are not written anywhere (despite there being written rules in multiple languages) that go against the rules of normal onsens. If and when you happen to break those rules, the unfriendly people will make sure to shame you for not knowing better.

On the top of everything, the water in the baths was way too hot. Probably around 44-50°C which wasn't even...

This hot spring is a unique place and a must-go while being in Yakushima. But when you go there you must respect strict rules and be aware of instructions. If you're not comfortable with onsen or nudity, don't go. Here are some information: the onsen is available just a few hours in the day. When the ocean is leaving, the onsen can be use and is facing the sea. This happens around noon and between 10pm and 2am 200 yens to use the onsen this onsen is shared, whichever the sex you MUST bring a towel to wear while using the onsen. You can't wear a swimming suit, it's forbidden. there is a small parking there are no changing rooms or showers. You will have to change in a car or find a way this is not an attraction but an experience. Don't take pictures as there are locals bathing! This is part of their lives and heritage.

If you're not comfortable in bathing with other people, even if you are wearing a towel, go during the night. There is much...

Feeling hot hot hot.

Went on a Saturday at midday (2 hrs before low tide) in September. Sun was shining, no breeze.

Middle pool is quite hot, two side pools mix with sea water for a warm experience. Pool on the right when facing the sea has some sharp rocks and flat rocks are slippery. Was painful walking there! Pool on the left is flat rocks, all quite slippery, easier to walk in.

It's a fun experience! Love the location, when we got there it was just us, quickly filled with people (all men) over the first hour.

It was hot in the baths and when I got out rather than feeling like the air was cool, the noonday sun, hot rocks on the ground, and no breeze meant I kept getting hotter and hotter. No shade and no coolness to be found nearby!

Would come back in evening or early morning when that fits the tidal schedule to avoid the noonday sun!

As other reviews mention: Only open 2hrs before low tide, 200¥ pp, naked and...