Oosterschelde National Park

The Oosterschelde is the largest national park in the Netherlands and most of it is water. When the estuary was closed at its mouth, the barrier was built with gates that stay open in normal weather, so the tide still runs in and out and the water stayed salt. What that preserved is a working sea arm: sandbanks that surface at low tide with seals hauled out on them, mussel and oyster beds farmed commercially, and porpoises that follow fish inside. It is also the main cold-water diving area in this part of Europe, with marked entry points along the dykes and cuttlefish arriving in spring to spawn. On land you get dyke roads, cycle routes, mudflats at low water and small harbour towns.

What you actually see

• Seals on the sandbanks - common and grey seals hauled out at low tide, usually seen from a boat trip.
• Shellfish beds - mussel and oyster culture worked from the harbours, visible as poles and boats across the water.
• Diving from the dykes - marked shore entry points used year-round, with cuttlefish appearing in spring.
• The dyke cycle routes - flat, exposed roads on top of the sea walls with water on both sides.

When to go

April to October for the mildest conditions on and around the water. Spring brings the cuttlefish that divers come for and the first seal pups on the banks. Autumn has the strongest light over the estuary. Tides govern everything: low water uncovers the flats, high water hides them, and the timetable shifts daily.

Honest expectations

There is almost nothing to walk through here; the experience is dykes, water and distance, which some visitors find monotonous. Wind is constant and there is no shelter on the sea walls. Diving demands a drysuit, current knowledge and tide tables, and is not a casual activity. Seal sightings from land are unreliable, boat trips are weather-dependent, and villages are very quiet off season.

Nearby

The storm surge barrier closes the mouth of the estuary, and the Zeeland beaches lie on the seaward side.