Mudflat walking: footing, etiquette and knowing when to turn back

The flats are not a beach

From the dike the exposed Waddenzee looks like a wide, level brown plain, and at the edges it behaves like one. Further out it is cut by channels that fill first and drain last, by soft patches of unconsolidated silt, and by mussel and cockle beds that are hard going and easy to damage. The surface changes between seasons and after storms, so local knowledge from last spring is not necessarily knowledge about this autumn.

The genuine hazard is not the mud itself but the combination of distance, a flat horizon and a returning tide. Water arrives from behind as well as in front, filling the channels between you and the shore while the ground under your boots is still dry. People who get into trouble here rarely do so because they fell; they do so because the route back closed while they were looking at something interesting. Fog makes this considerably worse by removing every landmark at once.

Why the long crossings are guided

Crossings to the islands, the classic wadlopen routes, are regulated in the Netherlands and are led by licensed guides who know the channel positions, carry communications, and plan the walk around a specific tide on a specific day. This is not bureaucratic caution. A guide reads the flat the way I read a tide table, and the route they take on the day may differ from the route they took a month earlier because a channel has shifted.

My own walking is limited to the near flats within clear sight of the seawall, at the bottom of the tide, with a fixed turnaround time written down before I set off. That covers a great deal of what I want to see: worm casts, cockle shells, lugworm holes, the ripples that record the last tide's direction, and the seals hauled out on a distant bank. For anything beyond that, going with people who do it professionally is both safer and considerably more interesting.

• Long island crossings: with a licensed guide, not alone
• Near flats: only in clear visibility, seawall always in sight
• Turnaround time written in the notebook before leaving the dike
• Fog forecast checked as carefully as wind and tide
• Phone charged and dry, but never treated as the safety plan

Footing, boots and cold

Bare feet or old trainers with a firm heel are the traditional answer, because the suction on soft ground will take a loose boot off and leave you barefoot anyway, some way from shore. I wear neoprene socks and cheap laced shoes I do not mind ruining. Deep boots are worse than useless: water comes over the top in the first channel, and then you are carrying it. Long trousers you can roll, and a dry pair in the rucksack for the train.

Cold is the underrated risk. Wet legs in a north-westerly in October pull heat away fast, and the walk back is usually into the wind because the pleasant outward leg had it behind you. I have turned around twice for cold rather than tide, and both times the decision felt premature and was not. Shell fragments and the sharp edges of cockle beds also argue for something on your feet even when the mud is inviting.

Leaving it as you found it

The flats and marshes are a protected area and parts are closed seasonally for breeding birds and for seal pupping; the closures are published and marked, and they exist because disturbance at the wrong fortnight has consequences that no amount of care afterwards will undo. Seals hauled out on a bank should be watched from a distance that does not make them lift their heads. If they are looking at you, you are already close enough, and probably closer.

Shells and worm casts are not litter to be collected, although a pocketful of empty cockle shells has never troubled anyone; live shellfish left where they are will still be there for the birds. Walking on mussel beds breaks them. Keep to the channels of firm sand where you can, take everything back including the apple core, and give any working fishing gear a wide berth. The flat recovers from footprints in a tide, which is the one forgiving thing about it.