Seiryu-so is a 5-star retreat in Izunokuni, Japan, located at Rendaiji Onsen 1. About 23,7 mi from the city center, this tranquil onsen haven invites travelers to unwind in luxury while soaking in the local springs.

Amenities shine with an outdoor swimming pool (free), a kids' pool, and an adults-only policy, complemented by a free spa and a free hot spring bath. A sauna (free), a bar, terrace, and garden add convenience and charm, while free Wi-Fi and air conditioning keep comfort constant. Free private parking on site makes arrivals easy, and non-smoking rooms, an elevator, free toiletries, and a bathtub complete the practical setup. For gatherings, meeting/banquet facilities are available for an extra charge, and massage services carry additional fees.

Seiryu-so has 199 reviews, underscoring a well-traveled reputation in this Izunokuni setting.

Two outdoor pools invite guests to soak up the sunshine: an adults-only heated pool with a shallow end for easy wading, and a separate kids-only pool for family splash moments. When it’s time to unwind, a complimentary spa and a free hot spring bath are ready, along with a sauna for a renewed sense of calm. A bar, terrace, and garden offer relaxed spots to sip and chat, while free Wi-Fi and air conditioning keep all travels comfortable.

Room options span a tempting range, including Vip Japanese Style, Suite (Garden View), Room With River View, Deluxe (View), Japanese Western Style, and Japanese Style Deluxe Suite. Additional choices like Japanese Style Superior and Deluxe Japanese Western, Mountain View, or Suite offer further variety. All listed rooms are non-smoking, with several layouts accommodating two adults (and a child in some configurations).

Payment options cover cash and major cards: American Express, Mastercard, JCB, Diners Club, Visa, NICOS, and UC. On-site parking is complimentary, and an elevator provides easy access around the property. With a calm Izunokuni setting and plenty of dining and lounging spaces, Seiryu-so offers a memorable onsen retreat experience.