Düne (Danish: Dynen, North Frisian: de Halem) is one of two islands in the German Bight that form the Archipelago of Heligoland, the other being Heligoland proper.

The small island of Düne is part of the German State of Schleswig-Holstein.

On New Year's Eve 1721 a big storm surge separated the dunes from Heligoland.

In 1940 the Nazi government increased the size of the island to 40 hectares (99 acres).

The Heligoland Airfield is still used today and has three runways, of which the longest is 480 metres (1,570 feet).