Mudflat hiking (Danish: Vadehavsvandring, Dutch: Wadlopen, Frisian: Waadrinnen, German: Wattwandern) is a recreation enjoyed by Dutch, Germans, Danes, and others in the Netherlands, northwest Germany and in Denmark. Mudflat hikers are people who, with the aid of a tide table, use a period of low water to walk and wade on the watershed of the mudflats, especially from the Frisian mainland coast to the Frisian islands.
The Wadden Sea, a belt of the North Sea, is well suited to this traditional practice. Belts of this shallow sea lie off the mainland of the Netherlands, between Friesland and the Frisian Islands; off the coast of northwestern Germany; and off the coast of southwest Jutland in Denmark.
In the Netherlands, mudflat hikers can walk from the mainland to Terschelling, Ameland, Engelsmanplaat, Schiermonnikoog, Simonszand, and Rottumeroog. Other mudflat hiking routes are known but are not recommended, either because of their inherent dangers (the correct path is difficult to follow and/or there are insufficient margins of error in timing the trip) or for the minimization of ecological disturbance, or both. In Germany, mudflat hikers can walk to the East Frisian Islands of Norderney, Baltrum, Langeoog, Spiekeroog, Minsener-Oldoog and Neuwerk. The North Frisian Halligen Süderoog, Südfall, Oland, Langeneß, Gröde, and Nordstrandischmoor as well as the island Föhr can also be reached from the mainland. There is also a connection between the islands Amrum and Föhr. For this specific route, a guide is mandatory.