Termas de Radium
- Location
- Guarda District, Beira Alta, Portugal
- Water type
- radioactive
- Temperature
- 35 °C
- pH
- 7.3
Water profile
Soothing — neither hot nor cold, perfect balance.
Rich in active gases or metals — a strong mineral character.
Soft water — natural, classic buoyancy.
Termas de Radium is a distinctive thermal establishment in Guarda, the highest city in Portugal and capital of Guarda District, where sulfurous mineral springs with naturally elevated radon content emerge from the ancient granite formations of the Beira Alta highlands, giving the spa its unusual name. The sulfurous waters here carry the therapeutic designation associated with trace radon content, historically prescribed in Portuguese balneology for musculoskeletal, neurological, and cardiovascular conditions. Guarda's position at over 1,000 meters elevation, combined with its medieval cathedral and well-preserved historic center, makes Termas de Radium an unusual urban spa destination where mountain heritage, historic Portuguese architecture, and traditional thermal medicine converge.