Though Yakushima is not a volcanic island, it is blessed with several natural hot springs (onsen 温泉 in Japanese). A unique feature is that a couple of the Yakushima onsens are actually by the sea and one of them is only accessible when the tide is low. You may be lucky enough to get the onsen and seaview all to yourself, or you could find yourself sharing it with elderly locals and other tourists.
Please follow the onsen etiquette of first washing yourself outside the bath (there are plastic washing bowls available for your use). If there isn't a shower available, simply scoop water out of the pool and thoroughly rinse yourself before getting in. It's fine to wrap a small towel around you or use a sarong to preserve your modesty, but the signs state that swimming costumes are not permitted. If your hair is long, put it up or wrap it in a towel to stop hair getting in the bath. Tattoos are still not the norm in Japan and, though no one will mistake you for a Japanese gangster (!), there are negative yakuza (Japanese mafia) connotations with tattoos. Better to save yourself an awkward situation and cover any tattoos whilst using the onsen.
About 10 minutes drive south from Onoaida you'll come to the tiny village of Hirauchi (平内). The sign for the onsen is visible on the left-hand side of the main road and it leads down to the Hirauchi or Kaichu (海中 meaning 'in the sea') seaside onsen. This onsen is only accessible twice a day for a couple of hours before and after low tide – you can pay a night time visit as well, but take a torch! To check the local tide times then click here. The longer you wait after low tide, the hotter the pools become.
The Hirauchi onsen is a popular stop-off on the YES Island Tour. If you would like to enter the onsen during the island tour then we can usually time our visit with the low tide. If you don't wish to enter the onsen then it's still worth a visit to see the beautiful setting, smell the sulphur and if you're lucky, come across some sunbathing fish (!). Plus you'll be able to take a close up look at the pools, which you can't do – politely – when they are full of naked people.
There are three pools: a foot bath (足) and a couple of small pools which you use to take water to rinse yourself before entering. The largest pool can fit 5 or 6 people. There are no changing rooms, so bring a plastic bag to put your clothes in and leave it on the rocks. As like most places in Japan there is, of course, a special place to take your shoes off. Make sure you do take your shoes off at the proper location as the locals get very angry when they see people trodding all over their onsen in shoes.
The onsen is unisex so use a towel or a sarong if you're feeling shy. There is a sign indicating that people with tattoos cannot enter the onsen (a common policy in Japan). A way round this is to cover visible tattoos with a band-aid or 10! The onsen costs 100 yen and you put your money in the honesty box at the top of the path before you enter. Don't forget to take a plastic bowl from the rack as well to use when rinsing yourself
The Hirauchi Onsen was not made as a tourist attraction, but it has become a tourist attraction. It has been used as a bath for the locals for 400 years and so please show respect for the onsen procedures when taking a bath.
The neighbouring village of Yudomari (湯泊) also has an onsen on its rocky beach. This onsen is slightly larger and not subject to the tide (unless there is a stormy sea). The onsen is divided into male and female sections with a narrow 1m high bamboo screen, so your modesty is protected – just! If you don't fancy getting naked with strangers, there is also a foot bath you can use for the 100 yen fee. This onsen is not particularly hot, so we recommned you avoid it in mid-winter. There are toilets, showers and a car park nearby. You can also snorkel close to the seashore at Yudomari.