Liepnitzsee circular hike and swim

We meet Gesundbrunnen SBahn platform 4 at 12.00 and take S2 Bernau train at 12.06. Change at Karow for RB27 towards Klosterfelde getting off at Wandlitzsee at 12.46.
We have the opportunity to swim at Wandlitzsee at the start or end of the hike, but the main part of the fun will be a leisurely hike around Liepnitzsee, stopping to swim out to the island and back. The hike is approx 15km and including swimming and breaks will take around 5 hours. We will finish at the Biergarten Wandlitzsee. It will be a relaxed hike, not a sprint, German and English speakers, and a relaxed break for non swimmers.
Please bring packed lunch, drinking water and a smile.