Shiroyama Hotel Kagoshima – Satsuma-no-Yu
The lookout open-air bath of a long-established hotel crowning Shiroyama hill above Kagoshima city. Facing Sakurajima across Kinkō Bay, the outdoor bath is celebrated as one of Kagoshima's finest views, and after dark the city lights and the smoking volcano's silhouette are magical. The bicarbonate spring from 1,000 m underground is a skin-smoothing 'beauty bath', offered in indoor and outdoor pools plus the 'Ion Spa' hot spring sauna. Day bathing runs 13:00–21:00 and costs ¥3,500 for adults (tax and bathing tax included), ¥3,350 for junior-high students, ¥1,750 for elementary pupils and ¥800 for infants. It is pricey, but face and bath towels are included and you can use the hotel lounge, the Ippinkan gift shop and restaurants, making it a popular splurge for the view alone; reservable private baths start at ¥4,950 on weekdays for day guests. A free shuttle bus takes about 15 minutes from Kagoshima-Chūō Station, or 10 minutes by car from Tenmonkan. Pair it with the Shiroyama observatory and Saigō Takamori's historic sites and make a soak facing Sakurajima the highlight of your trip.