Schlachtensee, Recreational lake in Steglitz-Zehlendorf, Germany.

Schlachtensee is a recreational lake in Berlin's Steglitz-Zehlendorf district offering space for various activities around its shore. A continuous path runs around the perimeter, connecting different waterfront areas and facilities.

The lake formed about 15,000 years ago as a glacial trough during the Weichsel ice age, part of the Grunewald chain of lakes on the Teltow plateau. In 1242 a Lehnin monastery charter recorded the village Slatdorp on the Slatse, which gave the lake its name. The surrounding area has belonged to Berlin since 1920.

The name Schlachtensee does not come from a battle: a 1242 Lehnin monastery charter records the village Slatdorp am Slatse, from Middle Low German slat, a wooden bank reinforcement or weir. Around 1750 a fisherman's hut was built on the shore, giving its name to the Alte Fischerhütte inn on the north-east bank, first mentioned in 1759 and 1767 and restored and extended in 2005.

The lake has swimming areas and boat rental spots, especially during warmer months. Good water quality and established paths make it easy for visitors to explore and try different activities.

The lake sits very close to an S-Bahn train station, making it easily reachable for a quick visit from the city center. This convenient location means visitors can walk from the station to the shore in just a few minutes.