This popular local recreation area is perfect for family weekend trips. At Eklundsnäsbadet, one finds a playground, two barbecue areas with multiple fire places and a nice sand beach as well as toilets and a kiosk which opens during the bathing season. According to Södertäljes website, the parking is free.
Nice and fairly expansive swimming area with many fireplaces. The lake is somewhat shallow at first so you have to walk a bit into the water before swimming. Seems to be a popular place.