Water activities
Scuba diving is not forbidden, but they way from parking would be very long, snorkeling would be much better idea. It would also not distrub the swimmers. It’s great for swimming or stand up paddling. There’s a SUP rental directly on the beach within the camping area (warning: paid entry).
Fishing
Türlersee is a fishing paradise. It’s very calm, and there are a lot of wooden piers dedicated for fishers - not for camping, not for sunbathing, but specially for fishing and observing nature. However, obtaining fishing license (160 CHF/year) requires membership in Sportfischer Vereins Türlersee.
Running / Walking
There’s a hiking trail around the lake. Its western part goes through the forest that gives shadow and has some grill stations and drinking water fountains. The eastern part has big recreational area and camping place.
@lechlukasz Türlersee - nature paradise at the foot of Albis #switzerland #lake #walking ♬ oryginalny dźwięk – lechlukasz - lechlukasz
Bird watching
The lake is surrounded by nature - there’s only one street with moderate traffic in the direct vicinity - which makes it great are to spot various birds. You can spot water birds: great crested grebe, eurasian coot, mallard, tufted duck, mute swan, common kingfisher, rails, herons, as well as land and forest birds: buzzards, falcons, red and black kite.