Marieviksbadet

Three unheated harbor pools built into the water at Marievik, just south of Södermalm, with a shallow children's pool and room for serious swimmers.

It was Stockholm's first harbor swimming spot, and it fills up on hot days. Between swims, ask at the bar of Plåtparken, the restaurant next door, about its glass-fronted private saunas looking out over the harbor.