Why tide times are the backbone of a safe coastal walk

The sea can move faster than you walk. On a flat sandy beach, an incoming tide can travel at a brisk walking pace, and sometimes quicker. A vast expanse of sand at low water can shrink to a narrow strip within an hour. Tide tables are not just for sailors or anglers; they are essential reading for anyone setting foot on a beach, causeway or rocky shoreline.

Tide times tell you when high and low water will occur, but the height matters just as much. A low tide of 0.5 metres exposes far more beach than a low tide of 3 metres. Around new and full moons, spring tides bring higher highs and lower lows, so more water moves in and out. Neap tides are gentler but can still catch you out. Always check the tide table for the exact date and the nearest standard port, then apply any local corrections.

How to read a tide table without overcomplicating it

Tide tables list high and low water times and heights in metres. Start by finding the closest standard port, then look for local adjustments. A table for one stretch of coast may be an hour or more out for a beach just a few miles away. Note whether times are in GMT or BST, especially around the clock changes in spring and autumn.

The rule of twelfths is a useful rough guide. Over roughly six hours of rising tide, the water rises in twelfths: one twelfth 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 water moves fastest. If you are walking on low-lying sand or mud, that is the time to be heading back, not pushing further out.

• Check the height, not just the time. A small tide may leave plenty of beach; a big spring tide can cover it quickly.
• Identify your turn-around time. Work backwards from high water and give yourself a generous margin.
• Beware of local quirks. Some estuaries fill faster than the table suggests because of channels and sandbanks.

Weather, swell and the sea's mood

A tide table is only half the story. Wind, air pressure and swell can push water higher and further inland than predicted. A strong onshore wind, combined with low pressure, can create a surge that lifts water levels by a metre or more. That can turn a safe-looking beach into a trap within minutes.

Swell matters on rocky shorelines too. Even at low tide, waves can sweep across ledges and cut off your return. Check the inshore waters forecast for wind direction, strength and wave height. If the wind is force 5 or above and blowing onshore, think carefully about exposed beaches and causeways. Rain makes rocks, seaweed and mud far more slippery. Fog can disorient you, making it hard to judge distance and direction. If conditions are poor, save the walk for another day.

Causeways, beaches and rocky shorelines: hazards by terrain

Different coastal walks demand different precautions. Causeways are among the most deceptive. Many flood twice a day, and safe crossing windows are often shorter than the full low water period. Holy Island in Northumberland, St Michael's Mount in Cornwall and Burgh Island in Devon are famous examples. Signs usually state that you should not cross unless you are sure of the times. For walkers, aim to cross at least two hours either side of low water, but always check local advice, because some causeways are only safe for a shorter window.

Beaches can hide sandbanks, channels and quicksand. In estuaries such as Morecambe Bay, the tide can come in faster than you can run. If you feel yourself sinking, spread your weight, stay calm and call for help. Do not struggle or thrash about. Mudflats are best avoided altogether unless you know the area well.

Rocky shorelines are slippery and sharp. Wet rock, algae, barnacles and limpets can cut or cause a fall. The incoming tide can wrap around headlands and cut off your return route. Always keep an eye on the sea behind you, not just ahead. Have an escape route in mind before you need it.

Local advice is worth more than any app

Talk to people who know the coast. Harbour masters, coastguard officers, local walking groups and even café owners can tell you about shifting sand, hidden channels and waves that appear on otherwise calm days. Car park notice boards often display tide times and local hazard warnings. Ask directly: "Is it safe to walk to that point and back before the tide?" If someone says no, listen.

Tell someone your route and expected return time. Carry a fully charged phone in a waterproof pouch. Know how to call 999 and ask for the coastguard. In remote areas, signal can be patchy, so consider carrying a whistle and a torch. A paper tide table or a printed sheet is a wise backup if your phone battery dies.

Before you set off: a simple coastal walking checklist

• Check tide times for the exact location and date, including whether clocks are on GMT or BST.
• Note high water time and height, then set a turn-around time with a generous buffer.
• Check the weather forecast for wind direction, strength, swell and visibility.
• Plan escape routes and avoid low-lying sand, mud or below cliffs at mid-tide.
• Wear grippy footwear and carry waterproofs, water and a phone in a waterproof case.
• Tell someone where you are going and when you expect to be back.
• If in doubt, turn back. The beach will still be there tomorrow.

Coastal walking is one of Britain's great pleasures, from the wide sands of North Norfolk to the rocky coves of Pembrokeshire and the causeways of Northumberland. With a little planning, respect for the tide and a ear for local advice, you can enjoy these places safely and come back with nothing worse than sandy boots and a good story.