Saitama is not usually spoken of as a single, well-defined onsen resort in the way that Kusatsu or Arima is. Instead, hot spring bathing in Saitama Prefecture is spread across a number of towns and day-use facilities, making it more of a practical local escape than a destination built around one famous spring quarter.
For travelers, that means a different kind of experience: less about postcard scenery or old resort streets, and more about slipping into everyday Japanese bathing culture within easy reach of Tokyo. If you are looking into “Saitama Onsen,” it is best to think in terms of individual baths and spa complexes across the prefecture rather than one historic onsen town with a single center.