There is something quietly marvellous about spotting a seal in the wild — a round head surfacing off a headland, or a beach of grey bodies dozing in the winter sun. But that pleasure comes with responsibility, because the animal you are watching is resting, feeding or raising a pup, and the moment it hauls back into the water because of us, it pays a price.

Why seals haul out — and why your approach matters

Grey seals and common (harbour) seals both leave the water for long stretches, and they are not simply sunbathing. Hauling out lets them digest food, warm up, moult and sleep. Seals are at their most vulnerable on land — heavy, slow and easily spooked, and every rushed entry into the water burns energy they have spent weeks building up.

That matters most in winter. A grey seal pup born on a beach in November or December has only a few weeks of rich milk before it is left to fend for itself. If a mother is pushed away from her pup by people crowding close, that pup can be abandoned. If you take one thing from this article, let it be this: distance is kindness.

Choose the right viewpoint before you set off

The best seal watching in the UK happens from a clifftop, a headland, a dune or a harbour wall — high ground with a clear line of sight and, crucially, no need to scramble down to the beach.

• Stay at least 100 metres from any hauled-out seal, and further if the ground is open and you are in full view. On a busy beach, 150 metres is a safer bet.
• Never position yourself between a seal and the sea. That escape route is the one thing it truly needs.
• Approach into the wind where you can — seals have a superb sense of smell, and your scent arriving ahead of you is a warning they cannot ignore.
• Keep dogs on a short lead and well away, even if they are impeccably behaved.

A drone, however small, can flush an entire colony into the water — and deliberately disturbing seals is a criminal offence under the Wildlife and Countryside Act 1981. Leave it in the car.

Getting the best out of binoculars and a zoom lens

A decent pair of binoculars is the single best piece of kit for respectful seal watching. Something like 8x42 or 10x42 is a good compromise: light enough to hold steady, powerful enough to read the expression on a face 200 metres away.

• Brace your elbows on a wall or rucksack, or lean against a rock, to stop the image shaking.
• Scan slowly along the tideline and out to sea, looking for movement that differs from the rhythm of the waves.
• Use a long zoom rather than walking closer. A tight crop is always better than a disturbance.
• Keep your voice low and your movements slow — sound carries across water far more than most people expect.

When pups are about: the extra rules of breeding season

Grey seals pup between September and December, with most UK births in October and November; common seals pup in June and July. During these months the rules tighten considerably.

Never touch a seal pup, even in the rain, even on a busy beach, even if it looks entirely alone. The mother is almost certainly watching from the water and will wait a long time before returning — but not forever. Keep children close, keep the pup's route to the sea clear, and if you are worried about an animal's welfare, report it to a local wildlife rescue or the coastguard rather than stepping in yourself.

Where an official viewpoint or roped-off area exists, use it. Many pupping beaches have volunteer wardens for exactly this reason, and following their guidance is the simplest way to do no harm.

Reading the signs — and what to do if you get too close

Seals tell you, quite clearly, when they have had enough.

• Head raised, staring at you — you have been noticed and the animal is on alert.
• Head and shoulders lifted, mouth open — a warning. Stop where you are and do not advance.
• Flapping or galumphing towards the water — it is fleeing. Back away slowly.
• A whole group moving at once — the haul-out has been flushed. Leave quietly and quickly.

If any of this happens, retreat the way you came, without running. Move slowly, keep low, and give the animals twenty minutes or more to settle. Often the wisest choice is to walk on and try somewhere else tomorrow.

A rough guide to the UK season

Autumn and early winter are the classic months. Grey seal colonies along the Northumberland coast, the Lincolnshire and Norfolk beaches, the Pembrokeshire islands, Cornwall's cliffs and the Scottish islands all fill up with mothers and pups. Summer is quieter for grey seals but busier for common seals, which pup on sandbanks and in estuaries where a rising tide can hide them. Whatever the season, early mornings and evenings tend to be calmest, and out-of-term weeks are a joy — fewer people, more seals, and a better chance of that unhurried look through the glass at an animal simply going about its day.