Drei Weieren, Urban park in St. Gallen, Switzerland.

Drei Weieren is an urban park with five connected ponds surrounded by walking paths, green spaces, and recreational areas at different elevations. The layout spreads across multiple levels, offering different views of the water from each section.

The ponds were built in the 17th century to supply water for textile bleaching and fire protection in the growing city. This early infrastructure was essential to the development of St. Gallen's textile industry.

The names Mannenweiher, Buebenweiher and Frauenweiher date from the early 18th century, when the ponds were first used for bathing and men, boys and women were separated. The Frauenweiher was formerly called Chrüzweiher, after a boundary stone carved with crosses marking the border between the city republic and the prince-abbey. Bathing was soon banned again because of noise during Sunday sermons.

The ponds lie on the slopes of the Freudenberg above St. Georgen and are reached by the Mühleggbahn; in summer, in good weather, a "Bäderbus" of the St. Gallen transport company runs from the station via Marktplatz to the entrance of the Frauenweiher. The Mannenweiher is a free municipal open-air bath with no access restriction, while the Frauenweiher charges admission. The Buebenweiher does not allow swimming because of its aquatic plants but is released for ice skating when the ice is thick enough.

The name Drei Weieren survives although there are five ponds today; at times there were seven. The Nellusweiher, dug in 1658, was filled in during 1920/21 as a work-creation scheme for the unemployed, and its site is now the lawn beside the Frauenweiher.