I keep wanting to tell you that we were deep within the marshes of Pas-de-Calais, which makes it sound like the hours I spent kayaking there were arduous and therefore worthy of admiration. But then I remember that there is no “deep” within the marshes of Pas-de-Calais. The network of canals and rivers in this UNESCO biosphere more closely resembles Manhattan gridlock than it does a dense jungle.

Just zoom in on Saint-Omer on Google Maps and watch as the splotch of green north of the town immediately turns into a set of intersecting blue lines. This skeleton of the marshes looks like a city grid surrounded by a suburban neighbourhood, complete with winding blue roads and cul-de-sacs.

And that’s precisely what’s so mesmerising and confounding about the Marais Audomarois, which has been an agricultural neighbourhood for over a thousand years. “Deep” within this ancient marshland, you’re rarely more than a few hundred feet from a road or a house. And yet you feel protected from the chaos of life and even the passage of time.

So protected, as if you are miles and centuries away from modern society, that when your phone rings long after you have forgotten about the inventions of email and mobile devices, you will be so surprised that you may overturn your kayak in a panic to silence it. (Hypothetically, of course. I certainly wouldn’t know from experience.)

The jetty for old wooden boats known as bacôves

I arrived in Saint-Omer last September with a kayak strapped to my back, determined to find a quiet break from London without travelling by car. I packed light — more or less. I brought a change of clothes, a friend and a pair of foldable, 18lb Oru kayaks, tucked into massive rectangular backpacks with bulbous drybags hanging off of them. Much to the amusement of our fellow Tube passengers, we brought these boats to France on public transportation.

We rode the Overground to the Underground to King’s Cross, took a train and a taxi to Dover, then a bus aboard the ferry to Calais. There, we boarded a shuttle to the city train station, and a train to Saint-Omer. And then we walked. All day, we counted up a dozen transfers and laughed about the sheer number of segments of our journey. All this so that we could paddle a pair of foldable plastic boats to La Fermette de Marie Grouette, a B&B you can’t drive to.

And you know what? I’d do it again.

Irrigation and cultivation in the Pas-de-Calais region

The Marais Audomarois was declared a UNESCO biosphere in 2013, but it has been an impressive example of human-curated nature for well over a millennium. Today, it’s a serene nature reserve that plays home to over 200 species of birds, including egrets and kingfishers. Leafy branches stretch across the narrower canals to create a shady, relaxing canopy, and it’s nearly impossible to resist paddling under the curtains of weeping willows.

In the Middle Ages, these waterways were much busier, when the people of Saint-Omer recognised wealth in the peat of the marshes surrounding the town. They drained the swamp, and in the 7th century they started digging. With simple tools, a vision and elbow grease, they eventually dug over 435 miles of navigable waterways and irrigation canals by hand. Little by little, they built a village of tiny farm islands. Rivers were their highways and wooden boats their lorries, piled high with peat, hemp and cauliflower. It was a thriving community much more populous than today, complete with its own local fairytales.

Kingfishers are just some of the birds you might spot as you paddle among the waterways

Up until the 1800s, at least 400 families made a living farming these waterlocked plots. But in the 1970s, roads and bridges were built to connect the islands to each other and to Saint-Omer, and that number dropped to half. Today, almost everyone is connected by land, but there are still about thirty homes in the marshes that are only accessible by water. It’s the only place in France where post is still delivered by boat year-round.

About 105 miles of waterways remain navigable today and homes are still scattered around the banks, including a handful of gîtes (holiday cottages) you can rent. One of these waterlocked houses is La Fermette de Marie Grouette, a colourful bed and breakfast with only two rooms. We arrived with plenty of time before dinner and, with little to distract us, the last few hours of afternoon sun stretched on the way they did at summer camp when I was a kid.

For dinner, our host, Muriel, served us a beautiful charcuterie board and we dined on a floating patio as the sunset turned the canal shades of fuchsia, violet and habanero. We felt isolated in the best of ways, and I can’t recall ever feeling so relaxed within such easy reach of restaurants and cinemas.

The guesthouse was named after Marie Groët, a mythical swamp witch. In a waterlogged metropolis centuries before the invention of armbands, parents couldn’t very well have kids running around the water’s many edges, thinking they were invincible before they learned how to swim. So, they used fear to keep their kids in line, and broadcast the cautionary tale of a beautiful (though grumpy) princess who turned into a toad-like swamp witch when she fell into the peat and disappeared.

You’ll see swans among the lily pads in Pas-de-Calais

The story goes that she had been picking flowers with her maid, Marie, using a wooden stick with a hook called a groët. When she fell in trying to pluck a flower that wouldn’t yield, she called for help. “Marie, la groët!” she kept shouting. “Hand me the hook!” But Marie just laughed until it was no longer funny, and by then it was too late – the princess disappeared, later becoming the swamp witch known as Marie Groët. Children were warned that she might snatch them by the ankle with her hook if they weren’t careful.

Today, the witch can be spotted most easily in the welcome video at La Maison du Marais, a beautiful and engaging museum explaining the history and ecology of the area. It’s a short and easy paddle here from the guesthouse, past scenic homes and a historic windmill.

While we brought our own watercraft so we could be nimble and not have to retrace our steps or rely on a car, you can easily rent kayaks, canoes, rowing boats and simple motorboats from a number of places around town. Les Faiseurs de Bateaux, a short walk from the Saint-Omer train station, is an excellent place to do so.

As the only surviving builders of traditional wooden boats called bacôves, their staff are well versed in local history and offer guided boat tours of the marshes. They also rent canoes, rowing boats and small wooden motorboats, and are the purveyors of detailed maps of the marshes. Their shaded patio is an excellent place for a pre- or post-paddle bite to eat.

A boat tour from Les Faiseurs de Bateaux on a bacôve, a traditional wooden boat

For a special treat, come between May and September on a market day, when O’Marais by Isnor organises vendors to hawk local produce from bacôves – much like it might have been done daily centuries ago.

Wherever you put in your boat, it’s easy to navigate the maze of waterways thanks to a simple but modern system of numbered signposts. Each intersection is marked with a number that corresponds to a recreational map of the marshes, so you can paddle endlessly through the marshes without ever being far from directions.

And of course, if you do get lost, there’s always Google Maps to provide a roving “you are here” marker that bobs along the canals with you. Just don’t forget to switch on airplane mode.

Need to know

Getting there: Crossing the Channel by ferry with a car is the fastest way to get here from the UK, though public transit is an easy (though time-consuming) adventure for paddlers with patience. The nearest train station is at Saint-Omer, a 45-minute ride from Calais-Ville. From there, you can walk to Les Faiseurs de Bateaux, where you can access an impressive network of canals, rivers and streams.

Best time to go: Late spring through early autumn for mild weather and a seasonal floating market.

Food: From May to September, O’Marais by Isnor arranges a regular floating market on the marshes, where you can buy local goods from traditional wooden boats called bacôves.

Where to stay: In town, book Hotel Mercure Saint-Omer Centre Gare, which has comfortable rooms near the town centre and an excellent breakfast with a crêpe buffet. In the marshes, stay at La Fermette de Marie Grouette, which can only be accessed by boat.

How to do it: The network of canals is vast and well-marked, once you get the hang of the numbered boxes posted at intersections.

Must-pack item: Stash your overnight kit in a waterproof dry bag to ensure your clean clothes stay dry on your journey.

Why go: The tree-lined waterways make the marshes feel separated from the busyness of modern civilisation, even as they are only minutes away from the conveniences of modern life. Adding to the feeling of an undiscovered gem, you won’t find many English entries in the guestbook at the guesthouse.