The Dieksee is 386 ha. He is traversed by the Schwentine. Via this waterway, it is connected to the other lakes in the Holstein Lake District (Kleiner and Großer Eutiner See, the Kellersee, the Großer and the Kleiner Plöner See and the Ukleisee).
Like the entire Holstein Switzerland, the Dieksee arose in the last ice age. Toteis had formed the lake bed.
Excursion boats (5 lakes ride) connect the villages Malente-Gremsmühlen, Niederkleveez and Timmdorf.
It is to be circumnavigated on a circular route of about 14 kilometers on foot or by bike.