Understanding Tide Times for Safe Beach Walking

Why the tide decides your walk

On the British coast, the sea rarely stays where you left it. A broad, firm expanse of sand at eleven in the morning can be knee-deep water by one, and the change often arrives faster than people imagine. Parts of our coastline have tidal ranges among the largest anywhere in the world, and on flat sand the water can advance at the pace of a brisk walk — sometimes quicker. Knowing your tide times is not a bit of background reading for a coastal walk; it is the single most important piece of planning you will do.

The good news is that the information is free, widely available and straightforward once you understand what you are looking at.

Reading a tide table without a degree in oceanography

Tide tables are published for specific reference ports, and the times shown apply to that location. A table for one harbour may be an hour or more out for a beach twenty miles along the coast, where the shape of the shoreline and the movement of the water can delay or advance the tide considerably. Ask locally which reference port applies to the beach you plan to walk, and whether a local adjustment is needed.

• High water and low water are the two extremes, but the interesting part for walkers is everything in between.
• Height matters as much as time. A low water of 0.4 metres exposes miles of sand; a low water of 2.1 metres leaves most of it covered. Two low tides on consecutive days are not the same beach.
• Spring and neap tides change the picture entirely. Springs, roughly every fortnight around the new and full moon, give the biggest range and the fastest-moving water. Neaps are gentler.
• Check the time zone. Most published tables use local time, which means British Summer Time in summer — a mistake here can put you two hours out of step.

Which way is the flood coming?

This is the question most people forget to ask, and it is often the one that matters. On a simple beach the sea comes in broadly towards you, but on many stretches of our coast the flood arrives sideways, along the shore, or by filling in behind a sandbank through a channel you barely noticed on the way out.

Estuaries are the classic example. Water pushes up the channel, spills over the banks and then spreads across the flats from behind, so a walker heading seaward can find the escape route cut off by a shallow but fast-moving ribbon of water that was dry sand twenty minutes earlier. Ask a local, or watch the water for quarter of an hour before you commit. Note which direction it is travelling, not just how high it is.

Plan the turning point before you set off

A useful habit is to decide your turnaround time before your boots are on, then treat it as fixed. Work backwards from the next high water, allowing a generous margin rather than a hopeful one.

• Aim to be back on a safe, dry route — ideally a slipway, promenade or cliff path — at least two hours before high water on an open beach, and longer where the ground is flat or the range is large.
• Use the rule of twelfths as a rough guide: over a six-hour flood, the water rises one twelfth of its range in the first hour, two in the second, three in the third, three in the fourth, two in the fifth and one in the sixth. The middle hours are when the sea moves quickest.
• Pick a return route that stays high and dry all day, not one that depends on the sand staying put.
• Tell someone where you are going and when you expect to be back, and carry a charged phone in a waterproof pouch.

Places and conditions that catch people out

Certain features deserve extra caution. Sandbanks and spits connect to the shore at low water and become islands as the tide rises, sometimes with alarming speed. Estuary channels widen and deepen within minutes. Headlands and rocky coves can trap walkers against a cliff with no way up. And quicksand and soft mud, common around many estuaries, slow you down precisely when you need to move quickly.

Weather adds another layer. A strong onshore wind and low pressure can push the tide higher and earlier than the table predicts. Fog and early dusk can hide a rising channel. If conditions are against you, the sensible walk is the shorter one.

If the water gets between you and the way back

Do not try to wade a channel whose depth you cannot judge — a metre of fast-moving water can knock an adult off their feet. Move to the highest available ground, stay put and call 999 and ask for the coastguard. Give your location as precisely as you can, using a what3words reference, a grid reference or a clear description of nearby landmarks. Then stay visible and conserve your energy.

A coastal walk is one of the great pleasures of living in Britain, and a little time spent with a tide table turns a nerve-racking outing into a confident one. Check the times, note the direction of the flood, fix your turning point, and you will always have the sand under your boots and the sea where it belongs.