The Centre Thermal is what brings most visitors to Yverdon. Five outdoor and indoor pools are filled with sulphurous mineral water emerging from underground at around 29°C, fed by a spring that the Romans were already using two thousand years ago. The water is rich in sulphate, calcium, and magnesium, and is officially recognised as a therapeutic spring for rheumatology and respiratory complaints.
The complex is a 1970s building, functional rather than glamorous, but the pools themselves are pleasant: a long outdoor basin facing the lawn, a covered grotto pool, a colder swimming pool, and various jets, currents, and bubble seats. A separate Espace Bien-Être with saunas, steam rooms, and quiet pools costs extra but is worth the upgrade for a couple of hours. It gets busy on winter weekends; weekday mornings are calmest.