Sennin-buro at Kawayu Onsen, Hongu – A Winter-Only Riverbed Open-Air Bath to Enjoy After Walking the Kumano Kodo

What Is 'Sennin-buro,' the Winter-Only Bath at Kawayu Onsen in Hongu-cho, Tanabe City?

Hongu-cho in Tanabe City, home to Kumano Hongu Taisha, has three hot spring areas, each with its own character: Yunomine, Kawayu, and Watarase. One of them, Kawayu Onsen, lies along the Oto River and is known as a hot spring village where simply digging into the riverbed causes hot water to well up.

In winter, part of the river is dammed off to create a huge open-air bath right on the riverbed. This is the famous 'Sennin-buro' (Immortals' Bath). The flow of the river, rising steam, and ridgelines of the surrounding mountains all come together in one view — a seasonal scene unique to Kumano in winter.

Whether it's set up, how long it stays open, and the conditions for bathing can change year to year depending on the river's condition. Be sure to check the latest official information from the local tourism association before you visit.

Why It Pairs So Well with a Winter Walk on the Kumano Kodo

In winter, the Kumano Kodo is a season when the air is crisp, there are fewer people, and the moss-covered stone paths and cedar groves feel even more hushed. At the same time, daylight is short, and the mountain valleys get colder than you might expect.

Warming a chilled body in a hot spring after a walk is a very Kumano way to spend the day, tied to the pilgrimage culture of healing baths (toji). Kawayu Onsen makes a great base for walking the old roads around Hongu Taisha, and it's easy to combine 'walking' and 'soaking' into a single day.

A Model Winter Day | Walk First, Then Soak

Morning: An Unhurried Walk on the Old Roads Around Hongu

Choose a short section of the old road around Hongu Taisha or along the approach, and plan backward from sunset with plenty of buffer time. In winter, 'not trying to do too much' actually makes the day more satisfying.

Midday: Visit Hongu Taisha and Have a Light Meal

Pay your respects at Kumano Hongu Taisha, and be sure to walk over to Oyunohara, the original site of the shrine, to feel the deeper atmosphere of Kumano.

Afternoon: Head to Kawayu Onsen and Enjoy the Bath

Make your way to Kawayu Onsen before the sun gets low. The scenery itself is the main attraction of Sennin-buro, so even if you don't bathe, just watching the steam rise from the riverbed gives you a true taste of winter in Kumano.

What to Know Before You Go

• Dress warmly: Wind blows across the riverbed, and you'll feel coldest just before and after changing clothes. Bring a jacket you can throw on, thick socks, and plenty of towels.
• Check bathing rules in advance: Whether swimsuits or bathing garments are required, and the available hours, can change. Follow the instructions posted on the day.
• Watch your footing and valuables: The riverbed is wet and slippery, and managing your belongings matters too. A waterproof bag gives you peace of mind.
• Plan for travel after dark: Roads back through the mountain valleys get dark quickly. Consider staying overnight, or plan to wrap things up early.

In Closing | A Winter Kumano Trip of 'Stillness' and 'Warmth'

The Sennin-buro you encounter at Kawayu Onsen in Hongu-cho, Tanabe City, is a scene you can only see in winter. After walking the crisp stillness of the Kumano Kodo, time spent wrapped in hot water by the river feels like a reward for choosing Kumano in this season.

Check the latest information, prepare for the cold, give yourself plenty of time, and enjoy a winter hot spring journey in Kumano.

Image: 川湯温泉　仙人風呂 (via (公社)和歌山県観光連盟)