Wild swimming in Slovenia with the man who conquered the world’s deadliest river

Maya Oppenheim

It is not too much to say that Martin Strel is the strongest man I have ever met. And when I say strong, I don’t mean in the muscular, Hercules sense; I mean strong as in indestructible.

The 63-year-old Slovenian may be a little rotund, but he’s also one of the world's elite endurance athletes. This unlikely hero is the greatest marathon swimmer to have lived, holding successive world records and claiming the accolade of being the only man to have swum five of the greatest rivers on the planet: the Yangtze, Parana, Mississippi, Danube and Amazon.

The latter is not just the largest in terms of volume, it’s also the deadliest swim. Strel conquered it while drinking two bottles of wine a day.

His various expeditions have seen him struck by lightning and knocked unconscious, as well as swimming alongside candiru – a bloodsucking fish known as the “vampire fish of Brazil”, which can swim up a urine trail into the penis. He has also swum with crocodiles and sharks, two animals he off-handedly describes as “friends”.

If that wasn’t enough, the former gambler and guitar teacher – the subject of Sundance award-winning 2009 documentary Big River Man, which follows him swimming the 3,300-mile Amazon – has been chased by machete-wielding native tribes.

But when Strel isn’t braving electrical storms and whirlpools, he’s a tour guide, having set up Strel Swimming Adventures with his son Borut in 2010.

Participants swim in some of Slovenia’s most beautiful lakes

Borut is not just a tremendously experienced swimmer himself, but has been his father’s project manager and expedition leader for years: together father and son have an unparalleled knowledge of open water swimming. But don’t let the dangerous scenes described above put you off their holidays. My Slovenian wild swimming adventure was one of the most tranquil and harmonious holidays I’ve ever had.

Before visiting Slovenia for the first time, the only thing I could tell you about it was that it had given birth to Slavoj Zizek, the eccentric continental philosopher otherwise known as the Elvis of cultural theory. Upon entering a land of fairytale castles, adorable churches and cobalt blue lakes, Zizek was the last thing on my mind.

At the intersection of the Alps, the Mediterranean and the Pannonian Plain, Slovenia is known for glacial lakes and rivers – ideal for wild swimming. The four-star Hotel Jezero acted as a perfect starting point, overlooking the blue-green waters of Lake Bohinj – and offering a reassuringly extensive breakfast buffet.

The trip involves swimming 4km per day

From swimming in lakes where the water was so clean you could drink it, to strolling through lush green forests and swimming under dazzling waterfalls, I felt like I was wandering through an oversaturated postcard in some far-flung mythical land. I’m struggling not to resort to cliche – it was magical.

A visit to Lake Bled – which, once you get past throngs of tourists, deserves its reputation of being one of the world’s most beautiful lakes – gave the chance to get under the skin of a well-worn attraction in a whole new way. Swimming to the 17th century church on tear-shaped Bled Island, and past Vila Bled, a former holiday residence of Yugoslav dictator Tito, I felt I was soaking up every last drop of the lake’s glistening glory – all while bathing in the shadow of the highest peaks of the Julian Alps.

Alongside the scenery, the people really made my trip. Something about getting into your swimwear with strangers – and I mean this is in the most wholesome way – and pulling on a brightly coloured swimming hat so your head looks like a painted egg, is curiously bonding.

Swimmers bond quickly on Strel Swimming Adventures

What’s more, solo swimmers are flocking to the tours, with around half the participants lone travellers. There’s a particularly large contingent of solo female travellers – a demographic which made up the majority of my group.

The average daily swim for the Slovenia trip was 4km, which, while it may sound a lot, flew by when fuelled by plentiful portions of Slovenian sausage and sauerkraut – plus endless entertainment and comedy from Martin and Borut. In fact, it was the guidance of the Strels – who relished showing us their homeland – that made the trip stand out from other swimming tours.

In one of many chats with Borut between dips, conversation turned to his father, and his intrepid adventures. Asked how Martin has managed to endure such gruelling swims while risking his life, his son told me: “His health is like a robot’s. He hypnotises himself to manage his pain and to filter out sensations in his head. He senses danger very differently to others. He does not recognise danger as danger, but as an object he will get around. In his perception, he can do anything.”

The adventurer himself was more crudely matter-of-fact about his ability to evade death.

“Physically you have hundreds of swimmers who are better than I am, but they are not mentally better,” he said. “The key is here.” He gestured towards his head, mouth full of the famous Lake Bled cream cake, a delicate puff pastry with cloud-like vanilla cream and custard.

“I can swim with crocodiles. I can swim with sharks. I can swim with whales. I can swim anywhere,” he continued. “They have never attacked me. I have a good relationship with animals. Just swim, don’t be afraid. In my mind they are friends. But of course this whole swimming thing is not for fun. It is a dangerous game. One mistake and it’s over.”

Travel essentials

Getting there

Wizz Air offers flights from London Luton to Ljubljana from £205 return.

Staying there

Strel Swimming Adventures offers tours aimed at all levels of swimmers. A three-night, four-day trip to Slovenia costs €570, including B&B accommodation. Excludes travel to and from Slovenia.