KAI Beppu

Kengo Kuma's bayfront 'onsen town under one roof': sea views from all 68 rooms and a festival in the lobby every night — but a small shared bath, shower-only standard rooms and uneven 2026 dinners

KAI Beppu opened in July 2021 on the seafront of Japan's biggest hot-spring town, and with 68 rooms it is by far the largest inn in Hoshino Resorts' KAI brand. Kengo Kuma designed it as an onsen town under one roof: stone lanes between black walls, a lantern-lit lobby with a 24-hour foot bath facing Beppu Bay, and persimmon-red rooms whose picture windows all face the sea. Japanese bloggers who stayed between 2022 and 2025 loved how the lobby turns into a night market after dinner — shochu stalls, smart-ball and moulding games, free self-made ramen and onsen eggs in past years — followed by the nightly 'onsen jug band', staff in happi coats drumming on wooden bath buckets. Sunrise over the bay is the other highlight. On one major Japanese booking site it rates 4.3 across 601 reviews, with rooms and cleanliness (4.6) the strongest scores and the bath (4.1) the weakest. The water is a salty spring with bicarbonate, free-flowing but with water added; there is a hot and a lukewarm indoor bath and a small, enclosed rock open-air bath, and a September 2026 guest found it lukewarm, topping out at 39°C. Dinner is a seafood kaiseki with Seki-aji or Seki-saba and a hotpot of spiny lobster, fugu and clams. But 2026 reviews are mixed: thin or rushed dinners, booths split only by bamboo blinds, dirt in some in-room baths, long walks and stairs to the bath and dining room, and parents who found it poorly suited to small children. Expect about ¥56,000–80,000 for two with meals, more with a private bath.