The coast is Britain's cheapest safari

You do not need a safari park ticket, a four-hour drive or a hide booked six months in advance to watch wildlife in Britain. You need a shoreline, a pair of binoculars and a bit of patience. Our coastline runs for thousands of miles and almost all of it is free to wander, from Cornish rock pools to Norfolk mudflats and the seabird cities of the Scottish cliffs.

The trick is knowing when to go and how to behave when you get there. Get those two things right and a family afternoon at the seaside can deliver seals, dolphins, oystercatchers and a bucketful of crabs for the price of parking. Get them wrong and you will see an empty beach, a wet coat and a lot of shingle.

Plan around the tide, not your diary

Everything at the coast happens to a timetable set by the moon. Before you set off, check the tide times for the exact stretch of shore you plan to visit — not the nearest big town, which can be an hour out. Harbour noticeboards, pier kiosks and tide tables sold in seaside shops are all reliable, and many coastal car parks display the day's highs and lows.

Two golden rules:

• For rock pooling, go on a falling tide. Aim to be on the shore about two hours before low water and leave the pools as the tide starts to turn. Rising water is what strands people on ledges.
• Never turn your back on the sea. Sneaker waves and fast-moving tides catch out experienced locals every year. Tell someone where you are going and when you expect to be back.

Weather matters too. A flat calm morning after a night of high pressure gives you the clearest water for spotting, while an onshore gale pushes birds closer to land and makes cliffs dangerous. Wind blowing off the sea is a good day for a sheltered estuary, and a bad day for standing beneath an overhang.

Rock pooling: a safari in a square metre

Rock pools are the most underrated wildlife habitat in Britain. A single decent pool can hold beadlet anemones, common periwinkles, dog whelks, shore crabs, hermit crabs and a butterfish or two. Look for the deep pools on the lower shore, the ones with weed fringing the edges — that is where the shy things hide.

Technique is simple. Approach slowly and stand so your shadow falls away from the pool, because fish and shrimps react to sudden darkness. Lift weed gently with your fingers, then put it back exactly as you found it. If you want a closer look, use a white tray or a clean ice cream tub filled with sea water, and return everything within ten minutes.

• Do use wet hands for anemones and starfish, and put stones back the same way up.
• Do not handle jellyfish, weever fish or anything you cannot identify. Some stings are genuinely nasty.
• Do not take shells, starfish or crabs home. They are not souvenirs, and most die within a day.

Cliffs and seabird cities: look, don't loom

Between April and July, our cliffs turn into the noisiest, smelliest and most spectacular free show in the country. Guillemots, razorbills, kittiwakes, fulmars and puffins crowd onto ledges, while gannets wheel offshore in long white lines. Add peregrines, choughs and the chance of a basking shark or harbour porpoise, and a cliff-top walk beats any screen.

The etiquette is straightforward. Stay on the path, keep well back from the edge — the grass that looks solid often is not — and give nesting birds at least 50 metres of space. Never walk along the base of a colony, and never fly a drone near one; disturbance can make adults desert eggs and chicks in minutes. Between 1 March and 31 July, keep dogs on a short lead near cliffs and on any beach where signs ask for it. Bring binoculars rather than creeping closer, and if birds start calling and diving at you, you are already too near — back off quietly.

Estuaries and mudflats: the quiet hour

Estuaries look like nothing much until you learn to read them. As the tide drops, thousands of waders spread out to feed: oystercatchers hammering mussels, curlews probing with those astonishing curved bills, redshank, dunlin and knot in restless flocks, and shelduck shepherding their broods across the mud.

Time your visit for the two hours either side of low water on a rising tide, when birds are pushed steadily closer to the shore and often right past a promenade or hide. In winter, estuaries are the place to be, holding teal, wigeon, pintail and Brent geese, plus the occasional hen harrier quartering the saltmarsh at dusk. Walk quietly, wear dull colours, and use a wall, a groyne or a car window as a makeshift hide. If birds lift off in a panic, stop moving for a few minutes and let them settle.

What to take, and what to leave behind

You can kit yourself out for very little. A pair of 8x42 binoculars is the single best investment, but even £30 compact pairs transform a walk. Add wellington boots, a warm layer, a flask, drinking water and sun cream — coastal sun and wind are deceptive. A small first aid kit and a charged phone in a waterproof pouch are sensible extras.

Leave behind the drone, the dog lead you forgot, and any urge to collect. Take home photographs, a tide table and a head full of guillemot noise. That is the whole cost of a day's wildlife watching on the British coast, and it is a bargain at any price.