It's 11.30 on Saturday morning at Bigbury on Sea car park. The sun is out, the sea is flat, seagulls are crying and so am I – from sunburn. Yesterday was the first day of sunshine since April and it took Dom and me by surprise. We're on a three-day swimming expedition in Devon and this is the finale: the circumnavigation of Burgh Island, home of an art deco hotel and many a mystery and Agatha Christie novel.
We meet a local friend, Jackie, and set off. Our journey's been plotted: anticlockwise around the island, past the spider crabs, around Cormorant Corner, through "Death Valley" and back to the start. We pay £1.50 to cross to the island on the elevated sea tractor that's used when the sandy spit that connects the island and mainland is cut off. We've timed our swim at the slack point of high tide to avoid currents, and the sea is flat and welcoming.
We tell the red and yellow lifeguards what we're doing. "Do you want us to send a lifeboat if you're not back in an hour?" they ask. We decline; while we're all secure swimmers we tend to dawdle and cloud watch on pretty swims, spending time inspecting bays and floating on our backs. The swim can take 40 minutes, but if we get distracted we won't be back in an hour.
The board by Burgh slipway tells us it's 14°C. We put on wetsuits, booties and silicon hats and wade in, in front of customers at The Pilchard Inn. I didn't know how tolerant people in this country are of "individuality" before I took up wild swimming: you can swim past fishermen in the dead of a November night or tread past a family of picknickers in what is, frankly, a ditch, and the most that people say is, "Is it cold in?"
I spuddle about in snorkelling position, all the better to find two spider crabs beneath me. "They're fighting!" I say. "How do you know they're not mating?" says Dom. We don't.
We turn the corner – dark grey slate rocks to our left, sea to the right. At the start of the swim we were in bucket and spade territory, with stripey windbreaks and ice cream. Now we're in sea that's properly wild.
"Once you get used to the idea that you won't get dashed against rocks, it's quite delightful," says Dom. Walkers from the cliff top above us look down as we swim between rocks and around Cormorant Corner. The dark black cormorants are there, eight lined up on a rock. Birds and fish seem unfussed by people once you're in the water, and we swim right up to them before they take off.
The coves and cliffs that looked forbidding from the cliff top (we checked out the swim from the land before we set off) now look beautiful rather than frightening. One cliff is a giant flat slab of slate, bright with reflected sun. We bob about and Jackie and I take a break with our feet on a rock.
"We're going through that gap," I say, pointing to Death Valley, a chasm between the island and a smaller outcrop. Dom thinks it's impossible; so did I the first time I swam here. It takes a leap of faith to swim through; waves carry you into the chasm and also push against you as you swim out. But the sea is mild so I'm sure it will be safe.
When we come out the other side we're two-thirds of the way around our journey. We can relax now, the wild section is over, but this side of the island is noticeably colder.
We launch a wetsuited assault on Burgh Island's hotel pool, a beautiful aqua lagoon with a private beach and a wooden life raft, and then feel guilty and jump back out into the sea.
There are no rip tides around Burgh Island and, although the tide is starting to go out, it's not much to swim against. Then we turn the final corner and get back to the beach, busy with sandcastle builders and kite surfers.
Swimming outdoors washes away all that goes before it, making a quick dip after work feel like a mini-break, and a Saturday morning swim feel like a complete holiday. As we step out of the water our eyes are a little brighter, our smiles a little broader: our weekend has begun.
Swim: Advanced. This 1.5km swim around an island takes swimmers past spider crabs, cormorants, dramatic cliffs and unseen coves.
Details: Bigbury on Sea is about 3 miles off the A379 from Plymouth to Dartmouth (nearest railway station, Plymouth). It is possible to get out at the beginning of this circuit, but after that you are committed.
Burgh Island Hotel (www.burghisland.com) is a wonderful place for a cocktail or slap-up meal afterwards.
Wild Swim: River, Lake, Lido & Sea by Kate Rew is available for £9.99 (RRP £12.99) with free UK p&p from the Guardian Bookshop.
