Bezirksamt Treptow-Köpenick übernimmt das Traditionsgelände von den Berliner Bäderbetrieben - Eintritt kostenlos
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Das Bad öffnet täglich jeweils von 10 bis 19 Uhr. Geplant ist, im Sommer die Öffnungszeit bis 21 Uhr auszudehnen und auch im Winter der Zugang zu ermöglichen.
Quelle: Welt online
Thanks for finding that for me! It's exactly what I wanted to know, and more besides. I was able to check your source, and found it was dated 10 June 2006. Hopefully they haven't changed their plans since, especially as far as winter access is concerned. I expect to visit Berlin in a few weeks.
For the benefit of other visitors to the International Section, here's what I've understood. The Treptow-Köpenick local authority is taking over the traditional [bathing] area from the Berliner Bäderbetrieben - Entrance free [ ... ]
The bathing place opens daily at the moment from 10:00 until 19:00. It is planned to extend the opening times until 21:00 and also to make access possible in the winter.