How to Check Tide Times Before Coastal Walks

Why tide times are the first thing to check

Anyone who has walked the British coast for long enough has a story about a beach that suddenly shrank, a causeway that looked perfectly passable on the way out and decidedly less so on the way back, or a quiet estuary channel that filled while they were photographing a wreck. The tide around our islands can move surprisingly fast. On broad, flat beaches such as those in North Norfolk or around Morecambe Bay, the sea can advance at walking pace or quicker, and on a spring tide it covers ground that looks like solid land for miles. That is why tide times, not weather apps, are the single most important piece of information before a coastal walk.

The good news is that the information is free, accurate and easy to find once you know what you are looking for. What follows is a practical routine you can use for any stretch of coast, whether you are planning a two-hour potter around a harbour or a serious low-water crossing.

Where to find official tide tables

Start with a proper tide table rather than a general forecast. In the UK, the reliable sources are:

• The Admiralty tide tables, published in printed and digital form, which cover standard and secondary ports around the UK and Ireland.
• Local harbour authority websites, many of which publish daily predictions, plus notices about seasonal changes or dredging.
• The nearest standard port, even if it is some miles away, as long as you understand the local offset. Tide times at a secondary port can differ by half an hour or more.
• Printed tide clocks and almanacs kept in many coastal shops, which remain useful because they rarely need charging.

Be wary of generic weather apps that show a single high and low water for a whole region. They often round times and ignore local quirks. If the app and the harbour notice disagree, trust the harbour notice every time, because it is based on a gauge that sits in the water you are about to walk beside.

Reading the numbers properly

A tide table gives you high and low water times and heights for each day. Three things matter for walkers. First, the time of low water, because that is your window for beaches, sandbars and causeways. Second, the height of the tide, since a low tide of 0.4 metres exposes far more ground than one of 1.9 metres. Third, whether it is a spring or neap tide. Spring tides, around the new and full moon, produce the biggest range and the fastest movement. Neaps are gentler, but never assume a neap tide makes a risky route safe.

The rule of twelfths is a rough way to judge how quickly water returns. In the six hours between low and high water, the sea rises roughly one twelfth of its total range in the first hour, two twelfths in the second, three in the third, three in the fourth, two in the fifth and one in the sixth. The middle hours move fastest. That is why the most dangerous moment on a causeway is often an hour or two after low water, when the tide is at its most energetic and the return route still looks clear.

Causeways, harbour notices and local signs

Tidal causeways and crossings deserve special attention. Some, such as those serving tidal islands, are covered twice a day and often have a short safe window of only a couple of hours either side of low water. Local authorities and owners frequently post the safe crossing times on boards at the start of the route, and these are usually based on a generous margin for safety. Read them, photograph them with your phone, and set an alarm rather than trusting your sense of time.

Harbour notices add the detail that tables cannot. They may warn of freshwater flooding after heavy rain, which can raise estuary levels above prediction; of military or training firing times on tidal ranges; of seasonal changes to buoyage or access; or of the speed of the incoming tide at a particular channel. If a notice mentions a specific hazard, it is because it has caught someone out before.

Planning your walk around the water

Once you have your times, work backwards. Decide your turnaround point and give yourself a buffer of at least an hour before the tide is due to reach your route, longer if the ground is flat or the walk is slow. Note that estuaries and rivers can run high even when the sea is low, because rainfall inland drains down after the rain has passed. Check the weather for the previous few days, not just the day itself.

Tell someone your route and expected return, carry a charged phone in a waterproof case, and keep an eye on fixed features such as rocks or groynes to judge whether the water is rising. If it is, turn back immediately rather than pressing on to a point that looks marginally higher. Fast-moving water on a flat beach is not a challenge to outrun; it is a serious hazard, and the coastguard would far rather hear from you early than late.

When the water moves faster than expected

If you find yourself caught out, move inland or to high ground at once and do not attempt to cross a deepening channel. Ring 999 and ask for the coastguard, giving your location and the state of the tide. Around the UK coast, low-lying estuaries and wide beaches can be cut off in minutes, so the safest habit is a simple one: check the table, read the notice board, set a turnaround alarm, and give the sea the respect it has earned.