 Leopoldplatz station first opened on 8 March 1923, along with the rest of the newly built line between the stations Stettiner Bahnhof (now Naturkundemuseum) and Seestraße, now part of the U6 line.Only much later on 28 August 1961 did the second, deeper platform open to serve what is now the U9 line.The building of this new platform involved a complete reconstruction of the older U6 platform, which was transformed from having a single island platform to having two platforms flanking the tracks.