Zip World Llechwedd (Bounce Below)

Llechwedd occupies part of a still-partly-active slate quarry above Blaenau Ffestiniog, a town that grew to around 12,000 people at the peak of the slate industry before its long decline through the twentieth century. Zip World has added adventure activities inside and around the old workings, alongside the slate caverns that Llechwedd was already known for.

The headline underground activity is Bounce Below: trampoline netting strung across multiple chambers of a cavern the operator describes as twice the size of St Paul’s Cathedral, with slides and a spiral walkway connecting the levels. Because it runs deep in the old quarry, the temperature stays a constant 6 to 8 degrees Celsius regardless of the season, which the operator markets as an all-weather activity. The same site also runs Titan, a seated zip line across two zones above the quarry workings, which Wikipedia lists as the longest zip course in Europe, plus a mine tour and underground golf.

It operates year-round apart from Christmas Day and Boxing Day. Betws-y-Coed and Blaenau Ffestiniog sit on the same Conwy Valley Line, so Llechwedd is reachable by train as well as by the roughly 12-mile drive over the Lledr Valley and through Dolwyddelan.

This suits anyone wanting an adventure activity that does not depend on conditions outside, and families with children too young for the more extreme zip lines elsewhere in the region. Anyone who dislikes enclosed underground spaces should skip it, since the whole experience takes place inside the old cavern workings. Velocity 2 at Penrhyn Quarry is the open-air alternative, 40 minutes north and considerably faster.