Kawayu Onsen Fujiya

Dig your own hot bath in the riverbed out front, soak in the winter Sennin-buro, and ride a free shuttle to the Kumano Kodo — a riverside base with real onsen character, in a dated building with patchy upkeep

Fujiya is a member of the Japan Association of Secluded Hot Spring Inns at Kawayu, the Kumano hot spring where water wells up through the riverbed: from March to November guests borrow shovels and dig their own steaming pool on the gravel in front of the inn, and from December to February the village builds the giant river bath Sennin-buro next door, open 6:30–22:00 (rental bathing wraps for guests). The inn itself is a five-storey concrete building with 31 rooms, all facing the river — mostly spacious tatami rooms, plus three 'Kumano Modern' rooms with Sealy beds and a river-view koyamaki-wood bath. Its own spring, a sodium bicarbonate-chloride water pumped at about 70°C, is cooled with added water but otherwise free-flowing, and a free 9:00 shuttle drops hikers at Hosshinmon-ōji or Fushiogami-ōji for the walk to Hongū. Foreign guests on one Kumano booking site rate it 4.52 across 209 reviews, but Japanese reviews are mixed — 3.45 across 11 on one site, with too few recent reviews for a score on another. Guests praise the river view, the bathing and kaiseki that some call fully satisfying; the complaints in 2022–2026 are about upkeep and staffing: cobwebs and dead insects on screens, stained sofas and algae in a Modern room's bath, dusty air conditioners, a plain breakfast, dishes served cold or pre-plated, and staff who couldn't explain the food. Expect about ¥16,500–27,500 per person with two meals, more for the Modern rooms.