Beyond the vermilion gate (a National Important Cultural Property) stands one of Japan's oldest surviving wooden bathhouses, built in 1876. Open from 6:30 am until late, ¥500.
A Gothic-style public bath recreating the Taishō-era 'Koyu Onsen'. Ureshino's silky bicarbonate water — one of Japan's 'three great skin-beautifying springs' — for ¥450, 6 am to 10 pm. Tatami rest room upstairs and private baths (¥2,500/50 min).
One minute from the Ureshino bus centre, the only day-spa in town with its own source (formerly Motoyu Onsen). Silky bicarbonate water — one of Japan's 'three great beauty baths' — in a large indoor bath, open-air pool and sauna. Many family baths (from ¥1,800/50 min + entry). Open 9 am–10 pm.
A cure-style resort in the Furuyu hot-spring hamlet up the Kase River, 30 minutes by car from Saga city. The signature is 'lukewarm' water at around 38 °C — the longer you soak, the more you unwind — long prized as a beautifying bath. The SHIORI bath complex has 15 kinds of baths including an open-air tub facing Mt Tenzan, lying and standing baths, a box steam bath, cypress tub and natural hot-sand bath, all from a private source yielding 43 tonnes a day. Day use 10:00–20:00, ¥1,300 with free face towel; Wednesdays from 15:00 only for maintenance. About 60 minutes by bus from Saga Station to Furuyu Onsen.
A municipal day-use bathhouse in the Furuyu–Kumanokawa spa area along the Kase River, about 30 minutes by car from central Saga. Kumanokawa's water is a radon-bearing radioactive (radium) spring, traditionally enjoyed as a long, slow soak at lukewarm temperature. The main hall has large and small pools at different temperatures, an open-air bath facing the hills, and a small sauna and cold plunge, all lively with local chatter. A barrier-free family bath (¥1,500 for 55 minutes plus admission) is available, and the tatami rest room offers meals and massage. Adults ¥600, children ¥350; open 10:00–21:00, closed the 3rd Thursday (next day if a holiday). Local vegetables are sold at the front desk, and the grounds have a hot-water stand and a 'Yu YOU Park' for car camping. Pair with Furuyu Onsen for a bath-hopping day.
A day spa on Route 202 in Karatsu, right beside Niji-no-Matsubara, one of Japan's three great pine groves, and an easy 10-minute walk from JR Niji-no-Matsubara Station. The mildly alkaline simple spring is used free-flowing and lives up to its 'beauty bath' name with a silky feel. There are tepid and hot tubs, an open-air bath, sauna and cold plunge, plus three private family baths (rock, barrel and so on; extra charge, booking until 20:00). Adults ¥800, children ¥450; open 10:00–22:00 (last entry 21:30), closed the third Thursday (open daily in January, February and August; special closure on December 31). The restaurant serves set meals with Karatsu fish, and as a pilgrimage spot for the anime 'Yuri!!! on Ice' the building has a fan display corner. Fits between Karatsu Castle, the Yobuko morning market and a drive along the pines, or as the finish to a day trip from Fukuoka — about an hour by car from the city. 50 parking spaces.
Takeo Onsen is famous for its vermilion gate, a National Important Cultural Property designed by Tatsuno Kingo, architect of Tokyo Station. Beyond the gate lie three public baths – Motoyu, Hōraiyu and Sagi-no-Yu – plus the private Tonosama-yu and Karō-yu, and Sagi-no-Yu is the only one with an open-air bath and sauna. Named for the legend of a white heron (sagi) healing its wounds here, its clear, refreshing mildly alkaline simple spring leaves skin smooth. Alongside the stone indoor bath are a rock-lined outdoor tub, a hot sauna, cold plunge and rest room, and generous hours from 6:30 in the morning to midnight (last entry 23:00) suit travellers. Adults pay ¥740 and children from 3 to elementary age ¥370; open daily except a maintenance break in mid-December. Soap and shampoo are provided, towels sold. About 12 minutes on foot from Takeo-Onsen Station on the Nishi-Kyūshū Shinkansen – a base for Takeo City Library, Mifuneyama Rakuen garden and nearby Ureshino Onsen.