Eryri is famous for what rises above it: jagged summits, glacial lakes, and ridgelines that draw walkers from across the world. Yet some of the region’s most remarkable experiences lie beneath your feet. Generations of slate and copper miners hollowed out chambers so vast that today’s adventure operators have turned them into trampoline parks, zip line courses, and even an underground hotel. If you are planning underground adventures in North Wales, this guide brings together the best of them, from the cavern practically on Bryn Bella’s doorstep to a Bronze Age mine on the Great Orme.
Bounce Below: Trampolining in a Slate Cavern
Inside Llechwedd Slate Caverns at Blaenau Ffestiniog sits a 176 year old chamber twice the size of St Paul’s Cathedral. Rather than leave it empty, Zip World strung it with trampoline nets, walkways, and slides taller than two double decker buses, creating Bounce Below. Visitors climb, bounce, and slide across six netted levels, with the highest reaching around 180 feet off the cavern floor.
Because the mine holds a steady temperature of six to eight degrees year round, Bounce Below runs whatever the weather does outside, making it a reliable rainy day plan. Sessions last about an hour, safety kit is provided, and children from age seven can take part alongside adults. It is roughly a 25 minute drive from Betws-y-Coed, or you can reach Blaenau Ffestiniog by train along the scenic Conwy Valley line. For more information click here
Caverns, Titan, and Underground Golf at Zip World Llechwedd
Bounce Below shares its mine with several other attractions worth combining into a full day out. Caverns is a subterranean assault course of rope bridges, via ferrata, and underground zip lines strung across the old workings. Nearby, the Deep Mine Tour carries visitors 500 feet down on one of Europe’s steepest cable railways, then on foot through ten chambers with guides who bring the Victorian slate industry to life.
Perhaps the most unusual attraction is Underground Golf: an 18 hole adventure course set across four levels, 500 feet below ground, reachable only by that same steep railway. Meanwhile, Titan takes a different approach, touring the dramatic manmade quarry landscape above ground before delivering over a kilometre of four person zip lines. Together, these adventures make Llechwedd one of the most complete underground days out in Wales.
Go Below: Zip Lines Just Down the Road from Bryn Bella
For genuinely wild caving and zip line adventure, Go Below Underground Adventures is based at Conwy Falls, only a few minutes from Bryn Bella. Their half day Challenge trip suits families and beginners, combining zip lines, a boat crossing, an abseil, and a waterfall scramble through a disused slate mine.
Braver guests can progress to Hero Xtreme, a demanding six to seven hour route through nine separate underground zip lines, including Goliath, the longest underground zip line in the world at 420 feet, and a 70 foot leap into darkness. The trip descends more than 1,300 vertical feet, the deepest publicly accessible point in Britain. Go Below has also opened Deep Sleep, an overnight stay in cabins built 1,375 feet down inside an abandoned Victorian mine, for guests who want to spend the night underground rather than just an afternoon. For more information click here
Great Orme Copper Mines: A Bronze Age Journey Beneath Llandudno
While Blaenau Ffestiniog’s mines date to the Victorian era, the Great Orme Copper Mines above Llandudno take you back roughly 4,000 years. Discovered by accident during landscaping work in 1987, this is the largest Bronze Age mine yet found anywhere in the world, worked using little more than stone hammers and bone tools.
A self guided route leads through 3,500 year old passageways to the Great Cavern, thought to be the largest manmade cavern created in that era, before returning past a Victorian shaft that plunges 145 metres. The visit suits every age and takes about 45 minutes, and it pairs naturally with a trip up the Great Orme by tram or cable car. Consequently, it makes an excellent contrast to the industrial mines further south: gentler underfoot, but no less remarkable in scale. For more information click here
Planning Your Day Underground
All of these sites stay a constant, cool temperature, so bring a warm layer regardless of the season above ground, and wear sturdy, closed shoes since floors can be uneven or damp. Most operators supply helmets and other safety equipment, though Go Below’s more physical trips ask that you book in advance and arrive with a reasonable level of fitness.
Because Blaenau Ffestiniog, Betws-y-Coed, and Llandudno sit within easy reach of one another, you could realistically combine two of these adventures in a single Eryri stay, particularly if you are already exploring the area’s other attractions and waterfalls. Get in touch with us at Bryn Bella if you would like help planning which combination suits your group best, we are always happy to point guests toward the right adventure for their nerve and energy levels.