Arima Onsen (有馬温泉, Arima Onsen) is an onsen, or hot springs in Kita-ku, Kobe, Japan. This Onsen is still a hidden treasure of modern Kobe, behind Mount Rokkō. It attracts many Japanese who want tranquility with beautiful natural surroundings and yet easy access from the busy cities in the Kansai metropolitan area including Osaka. Arima Onsen was named in the Heian-period The Pillow Book as one of the three famous springs in Japan. It was selected as the most prestigious hot spring during the Edo period.^[1]

This onsen is one of Japan's oldest, with Dōgo Onsen in Ehime Prefecture and Shirahama Onsen in Wakayama Prefecture. Many documents since the 8th century AD mention this onsen.

According to these documents, among the many visitors to Arima Onsen are Gyoki (行基), a charismatic Buddhist monk in the 7th century, and Ninsai (仁西), another monk in the 12th century. Ninsai was said to greatly admire Arima Onsen and helped develop it. Hideyoshi Toyotomi visited this onsen several times in the 16th century.

Arima Onsen has two kinds of springs. One is kinsen (金泉, "gold spring"), which has water colored yellow-brown from iron and salt. The other is ginsen (銀泉, "silver spring"), which is colorless and contains radium and carbonate.

In 2007, there were more than 20 hotels and inns in the Arima Onsen area, with Arima Grand Hotel being one of the largest in the area.^[2]

• Kin-no-yu
• Zuihoji Park
• Tudumi-ga-taki Park
• Arima Grand Hotel
• Ryokan Gosho-bessho
• Tokyu Harvest Club Arima Rokusai
• XIV Arima Rikyu

• Tosen Goshobo – an historic ryokan (Japanese inn) located in Arima Onsen
• Three Ancient Springs