Wadlopen — walking across the exposed Wadden Sea mudflats at low tide — is one of the stranger and more memorable things you can do in the Netherlands. When the tide retreats, kilometres of open seabed appear between the mainland and the islands: wet sand, channels, cockle beds, and a vast empty sky. Seals are occasionally visible on distant sandbanks. The Wadden Sea is a UNESCO World Heritage Site, recognised for its extraordinary tidal ecosystem.
Tours must be booked in advance through licensed guides — walking the flats without guidance is illegal and genuinely dangerous; tides come in fast and channels can appear without warning. Guided crossings to Ameland (with ferry return) are a full-day undertaking. Shorter guided walks from the shore are also available. The season runs roughly May to September, depending on tidal conditions.