Terschelling is an island in the northern Netherlands, one of the West Frisian Islands. It's longstretched and narrow, so from a high dune top you can see the North Sea in the North, and the Wadden Sea in the South. Viewpoint Kaapsdune, Oosterend. To the North, the broad dune belt and North Sea under a blue sky. Panorama. Terschelling, province Friesland, the Netherlands.