This idyllic corner of Wales, now known by its Welsh name Eryri, has had an extreme makeover and been transformed into what is arguably the adrenaline capital of Europe, writes Fiona Whitty.

Visitors were once lured to Snowdonia national park by superb scenery, mountain railways, hill walking and quarry tours, the latter harking back to its time as the slate capital of the world.

Nowadays, it’s home to a string of ground-breaking thrills like the world’s fastest zip line and the first ever inland surf lagoon while some of its old slate mines have been converted into unique experiences such as a 5km-long underground assault course.

But does it beat Queenstown for high-octane fun? Take a look at our pick of Snowdonia’s hardcore adventures that could rival New Zealand’s.

World’s fastest and Europe’s longest zip line

The record-breaking Zip World Velocity 2 will have you soaring at speeds of up to 160km/h for 1.6 km while dangling above a quarry lake. For an extra thrill flyers hurtle head-first, face-down. Its creators claim it’s the “closest you’ll come to experiencing what it’s like to fly”. If this sounds terrifying, there’s a shorter and slower practice line beforehand to make sure you can hack it.

The world’s fastest and Europe’s longest zip line exists in Eryri, Wales. Photo / Keith Freeburn

England and Wales’ tallest mountain

There are six different routes up to the 1085m summit of Mount Snowdon, the highest peak in the UK outside of the Scottish Highlands. All are classed as hard/strenuous but, for hardcore hikers, the most challenging is the Watkin Path, which ascends steeply and includes sections of scrambling. The mountain recently reverted to its Welsh name of Yr Wyddfa.

There are six different routes up to the 1085m summit of Mount Snowdon. Photo / Getty Images

A seven-hour underground assault course

If you like clocking up unsurpassed feats you’ll love Go Below, a series of underground adventures in a disused Victorian slate mine. Its Ultimate Extreme circuit, dubbed the UK’s scariest assault course, is 5km long, takes seven hours to complete, is lit solely by helmet lamps and plummets as low as nearly 400m below Snowdonia’s mountains – the deepest accessible point in the whole of the UK. Features include the world’s longest underground zip line, its first underground seated zip ride and its first underground free fall where you jump into a 21m abyss.

Go Below features a series of underground adventures in a disused Victorian slate mine. Photo / Keith Freeburn

Wild swimming in deserted lakes

Snowdonia has several hidden-away lakes that are accessible only on foot, often ensuring peace and solitude. Llyn Eiddew-Bach is a 45-minute walk from the nearest road so is a good bet for a swim on your own. With cliffs ideal for leaping off and amazing sea views, it’s buried in the untamed wilderness of the Rhinogs, probably the least visited peaks in the national park. Alternatively, Llyn Du’r Arddu is a deep blue lake lying under the steep rocky crag of “Cloggy”, dubbed “the shrine of British climbing” because of its concentration of extreme routes.

Surfing . . . 11 km inland

You can soak up head-high waves without ever dipping your toes in the sea at what was the world’s first-ever inland surf lagoon. Waves tumble along every three minutes in the 300m purpose-built freshwater pool at Surf Snowdonia, part of Adventure Parc Snowdonia. For an added perk, surf fanatics can sleep overlooking the lagoon at a Hilton Garden Inn – or in a quirky camping pod.

Experience the world’s first-ever inland surf lagoon in North Wales. Photo / Visit Wales

World’s first tandem drop

At Zip World’s Plummet 2, thrill seekers can stand in pairs on a trapdoor at the top of 30m tower . . . and wait for it to open. They’ll freefall at first but Powerfan technology ensures a soft landing.

White-water rafting with Olympic-grade rapids

Obstacles with names such as Ski Slope and The Graveyard should provide a clue as to how intense one of the courses at the National White Water Centre is. A dam release on the River Tryweryn ensures rigorous rafting at grades 3 and 4. The hardcore should try orca extreme – the chance to tackle the rapids in a two-man raft.

A unique twist on an old favourite is Zip World’s adventure golf course buried deep inside an abandoned cavern. Opened this year, the 18-hole Underground Golf is set across four floors 152m below the surface, with neon lights and loud music for company. Even getting down to it is record-breaking . . . it’s accessed by a ride on Europe’s steepest railway.

Extreme mountain biking

Britain’s first ever purpose-built singletrack mountain bike trails were created in Snowdonia’s Coed y Brenin Forest Park in the 1990s. Now the park is home to 145km of tracks, including the 35 km long The Beast. With rock drops and monster climbs, it’s the bike equivalent of a black run in skiing. Elsewhere, the 14 trails at Antur Stiniog range from novice to world-cup racer and are accessed by an uplift service that operates all day.

Snowdonia’s Coed y Brenin Forest Park is home to 145km of mountain bike tracks. Photo / Visit Wales

For more things to do, see visitwales.com