The Upper Germanic Raetian Limes, the fortified border of the Roman Empire, boasts impressive remains near Bad Ems. Recognized as Germany’s largest archaeological monument and a UNESCO World Heritage Site since 2005, it is uncertain whether the Romans ever utilized the town's thermal springs during their presence here.

Bad Ems was first mentioned as a town in the 7th century, but it wasn’t until the 14th century that a “warm bath near Ems” was recorded. In 1382, a tower house was built over one of the thermal springs, with prominent local families adding bathhouses in the 15th century.

By the early 18th century, Bad Ems had become one of Germany’s most popular spa towns. New bathhouses, pump rooms, and a casino (operational until 1872) boosted its popularity. In the 19th century, state ownership led to an expansion of spa architecture. The introduction of the Emser Pastillen in 1855, inspired by the Vichy pastilles, solidified its reputation as a center for innovative treatments.