AquaFonte lists 3 verified thermal springs in Belgium, each with its own page: temperature, minerals, treatments, and directions.
Water types found
Springs
Château des Thermes
Liège Province (Chaudfontaine) · 37°C
Belgium and the Benelux's only naturally hot mineral spring, feeding a luxury thermal spa hotel in Chaudfontaine, where water surfaces at around 37°C after a decades-long underground journey.
Spa — Les Pouhons
Liège Province, Ardennes · 11°C
The city whose name became a universal word — cold iron-rich carbonated springs used by European royalty since the Renaissance.
Thermes de Spa
Liège Province, Ardennes
A modern glass-and-curves bathing complex perched on a hilltop above the town of Spa, using the same natural cold, iron-rich carbonated mineral water as the historic Pouhon springs, reached by its own funicular.