I wake and listen for a while to the crash of surf rolling up the beach. Peeping out of the tent door, the tide is in, the sun is bright, and there’s salt spray in the air. The sea glows turquoise and the cove lies empty, a stretch of pearly sand backed by dune.

For the past few years I’ve been journeying around Britain, researching a new wild swimming book on secret coves. The beach and sea have become my camping buddies, the last things I see at night and the first sounds that greet me when I wake.

An heroic plunge into the early morning breakers is my first professional task of the day, and in an instant I am transformed from a groggy mass of sleeping dust and pyjamas to a full-awake human being, splashing, squealing and alive.

I don’t last very long on these early morning dips but, dripping on the sand afterwards, tingling all over, the natural high quickly kicks in. Forget coffee, this is the real deal. I always need to dive back in.

People ask what it is about camping by the sea that is so seductive. Swimming is certainly part of it, but on a practical level I’ve also found the beach to be a provider and a good friend. The sand moulds happily to the shape of my hips, and there’s water for washing up and driftwood for a fire.

I can even gather a bit of dinner too. Often I’ll wander off and find marsh samphire, cockles and sea beet, a complete meal and a forager’s dream, delicious with a bottle of chardonnay that’s been chilling in a nearby rock pool.

For families, too, all the entertainment is at hand. For the sporty you can mark up all manner of courses and courts: for volleyball, boules, crazy golf, obstacle races and countless variations of the comedy Olympics.

The more arty, or those who fancy themselves as an aspiring Goldsworthy or Gormley, can make zen gardens from pebbles or collages from seaweed. And if you’re short of inspiration try a scavenger hunt — a great way to help keep the beach clean too — and make some sculptures from flotsam.

I used to head for the mountains when I was feeling drained by the city, but now I’ve realised that the coast is nearer, and just as wild. As the sun melts over a shimmering horizon, the campfire sparks race into a darkening sky and the stars emerge in the purple abyss, the senses are filled. The sheer immensity calms the mind and soothes the soul.

In Norfolk, I get this same feeling when I walk out at low tide to dip in Blakeney Point, where the seals come up to me nuzzle me as I swim. In Dorset, I feel it beneath the towering Purbeck Cliffs, where grassy knolls lead to honey-coloured rock platforms perfect for diving, snorkelling and skinny dipping. In Scotland the feeling comes from the hue of the water as it glows azure.

But I can find it even close to London when, on a warm midweek evening after work, I’ll sometime jump on the train to Norman’s Bay, near Pevensey, East Sussex, and be on one of the wildest beaches on the South Coast within an hour. Camping, surfing, watching the sun go down, this is a place for fires, songs and night swimming.

I return with the commuters the next morning, salt in my hair and sand in my shoes, the cobwebs blown away, all happy and smug with the adventures that beach camping can bring.

Wild Swimming: Coast, by Daniel Start, £14.95 from www.wildswimming.co.uk