Beginner's Guide to Snorkelling in British Seas

Why British waters deserve a second look

Ask most people to picture snorkelling and they will conjure coral reefs and turquoise lagoons. Ask them about the sea off Cornwall in April and you will get a grimace. That grimace is out of date. Between roughly March and late May, before the spring plankton bloom turns everything green, British coastal water can be genuinely clear. Ten to fifteen metres of visibility is not unusual off the west coast of Scotland, around the Isles of Scilly, along Pembrokeshire or in the clearer corners of Cornwall and Northumberland. It is cold, yes. But it is the same water that feeds kelp forests, seagrass meadows and some of the richest rocky reef in Europe, and much of it lies within paddling distance of a car park.

The kit that keeps you warm

Cold is the single thing that ends a first snorkelling trip early. Get the thermal layer right and everything else becomes enjoyable.

• Wetsuit: a 5mm full suit is the summer minimum around most of the UK; for spring, autumn or anywhere north of Yorkshire, look at 7mm or a semi-dry. Water can still be 8°C in April.
• Hood, boots and gloves: non-negotiable. You lose heat quickly from the head, hands and feet, and you will last far longer with them.
• Mask and snorkel: a well-fitted mask matters more than an expensive one. Hold it to your face and breathe in gently through your nose — it should seal without the strap. A simple purge-valve snorkel is plenty.
• Fins: open-heel fins worn over wetsuit boots are easier to pull on and warmer than full-foot versions.
• Surface marker buoy: a bright towed float with a flag, on a short line. This is the piece beginners most often skip, and the one that matters most on any beach with kayaks, anglers or boat traffic.

A weight belt of two to four kilos, adjusted to your suit, stops you bobbing like a cork and makes it easier to lie flat on the surface. A small torch helps when peering under ledges. If you are buying for the first time, hire a full set from a dive centre or club for two or three trips before committing — you will learn what actually fits.

Choosing your first spot

Look for a sheltered bay with a gentle slope, easy shore access, rock or kelp at the edges and sand in the middle. Sand means straightforward entry and exit; the rocks hold the life. Avoid anywhere with a reputation for strong currents, and leave exposed headlands until you have a few trips behind you.

West-facing coasts tend to be clearer than the shallow, silty North Sea, though there are lovely exceptions in Northumberland and the Scottish sea lochs. Estuaries and sheltered channels often give the calmest water, but they also carry the strongest tidal streams, so check before you get in. The reliable approach is to ask locally — harbourmasters, dive clubs, angling shops and lifeguards all know which bays behave on which tide.

Tides, weather and staying safe

The sea around the UK moves more than most visitors expect. A bay that is a paddling pool at high water can drain into a maze of channels within a couple of hours.

• Snorkel at slack water. Aim for an hour either side of high or low tide, when the current is weakest. Neap tides are calmer than springs.
• Check wind direction, not just speed. An offshore wind pushes you out while flattening the water, which makes it deceptively inviting. Settled light winds over several days usually give the best visibility.
• Never go alone. Snorkel in a pair, or with someone watching from shore. Tell someone where you are going and when you expect to be back.
• Enter gradually. Cold water shock is a real risk even in August. Wade in, let your suit flood and warm up, and breathe steadily through the snorkel before putting your face down.
• Know your exit. Pick a landmark ashore and work out where you will get out if the tide turns or the wind picks up.

What you might see

Ballan wrasse, pollock and gobies dart through the kelp while blennies peer from cracks. Look under overhangs for velvet swimming crabs, edible crabs and the occasional lobster, and scan the sand for flatfish and rays. Spring brings cuttlefish inshore to lay their eggs, and dogfish and catsharks cruise the shallows. Basking sharks pass through the south-west in late spring, and grey seals often come to investigate — keep your distance and let them choose the encounter. Seahorses live in seagrass beds at a handful of sheltered southern sites, and you may spot one if you hover quietly above the blades.

Snorkelling lightly

Everything you see is fragile in ways that are not obvious. Kelp, seagrass and maerl — the pink, twiggy seaweed that builds up over centuries — take years to recover from a misplaced fin.

• Do not touch, chase or feed. Handling fish strips away protective mucus; chasing burns energy they need.
• Keep fins off the seabed and stay a metre above the reef. Never stand on rocks or weed to rest — float, or head back to the beach.
• Take litter out with you, but leave living creatures and historic wreck material where they are.
• Check, clean and dry your kit between sites. Invasive species travel in trapped water and grit on wetsuits, fins and buoy lines.
• Record what you see. Local marine conservation groups and wildlife recording schemes rely on sightings from ordinary snorkellers, and your notes can help protect a site.

Start small, start shallow, and start in spring. A sheltered bay on a calm neap tide, with a well-fitting suit and a float above you, is one of the best introductions to the sea this country has to offer.