Obama Onsen — Longest Hot Spring Footbath in Japan

Published: Jun 1, 2026

Updated: Jun 1, 2026

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Obama Onsen — Longest Hot Spring Footbath in Japan

Obama Onsen is a coastal hot spring town facing the Tachibana Bay, known for having the highest water temperature of any onsen in Japan — the source emerges at 105°C, making it unsuitable for bathing without cooling. The town's solution: a 105-meter-long public footbath (Hottofutto 105) running along the waterfront, where the spring water is cooled to 42°C and visitors can soak their feet while watching sunset over the bay.

The footbath, opened in 2010, is free and accessible 24 hours. Benches line the entire length, and the water depth (30cm) allows comfortable soaking while seated. The length (105m) refers to the source water temperature (105°C) — a playful naming convention typical of Japanese onsen marketing.

Opening Hours

Hottofutto 105 footbath: open 24 hours | Obama Jigoku steam cooking facility: daylight hours (check on-site)

Closed: Open year-round

Entrance Fee

Footbath: free | Obama Jigoku steam cooking: ¥100 for 20 minutes | Towel: ¥200 at nearby shops if needed

Best Season

Year-round | April–September for sunset foot-soaking with bay views | Summer evenings for the most social atmosphere

Visit Duration

30–60 minutes (footbath) | 2–3 hours with jigoku cooking, waterfront stroll, and ryokan day-use onsen

Getting There

Access Information

Obama-cho, Unzen City. 30-minute bus from Isahaya Station. The footbath runs along Obama Marine Park waterfront. Free, open 24 hours. Bring towel (sold at nearby shops for ¥200 if forgotten).

Insider Guide

Premium

**Sunset timing:** The footbath faces west across Tachibana Bay toward the Shimabara Peninsula. Sunset from April to September sets directly over the water, and the foot-soaking position with sunset v