It has an area of Шаблон:Convert, a maximum length of about 3.4 kilometres and a maximum width of 1.6 kilometres.
The lake is up to 38 metres deep, its surface elevation is about Шаблон:Höhe and it is crossed by the River Schwentine from east to west. This waterway links the Dieksee to the other lakes in the Holstein Lake District (the Kleiner- and Großer Eutiner See, the Kellersee, the Großen- and Kleinen Plöner See and the Ukleisee).
Like the rest of Holstein Switzerland, the Dieksee was formed during the last ice age. Dead-ice was preserved in the hollow thus formed; when that melted the lake was formed.
Recreation
Boats may use the lake and pleasure boats (run by 5-Seen-Fahrt) link the largest villages of the Holstein lake district. In the villages of Malente-Gremsmühlen, Niederkleveez and Timmdorf there are jetties on the Dieksee. There is a circular walk and cycle path around lake which is about 14 kilometres long. From the Holzberg Tower there is a good overview of the Dieksee, the lake's islands of Langenwarder and Gremswarder and the other lakes in the region.
