Dieksee
Dieksee
Location	Holstein Switzerland, Schleswig-Holstein, Germany
Coordinates	54°09′58″N 10°31′15″E / 54.16611°N 10.52083°E / 54.16611; 10.52083
Primary inflows	Schwentine
Primary outflows	Schwentine
Basin countries	Germany
Surface area	386 ha (950 acres)
Max. depth	38 m (125 ft)
Surface elevation	22 m (72 ft)

The Dieksee is a lake in the Holstein Switzerland region of North Germany.

It has an area of 386 hectares (950 acres), 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 22 m above sea level (NN) 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.

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.

Panorama of the Dieksee from the Dieksee promenade in Malente-Gremsmühlen (Dec 2009)

• List of lakes in Schleswig-Holstein

• Media related to Dieksee at Wikimedia Commons
• Data on the Dieksee at umweltdaten.landsh.de (in German)
• Stephan, H.J. (2003) Zur Entstehung der eiszeitlichen Landschaft Schleswig-Holsteins (The Formation of the Ice-Age Landscape of Schleswig-Holstein) Archived 2018-04-10 at the Wayback Machine (in German)