At a glance
Guided 4–5 hour underground adventure in Victorian slate caverns above Blaenau Ffestiniog — via ferrata, abseiling into flooded chambers, rope bridges, and zip lines inside vast unmodified cavern spaces. Ages 10+. From ~£65. Advance booking essential. LL41 3NB.
About Go Below Underground Adventures
Go Below operates guided adventure experiences inside the Cwmorthin and Rhiwbach slate caverns above Blaenau Ffestiniog — vast Victorian underground workings that extend hundreds of metres into the hillside above the town. Unlike the commercial slate cavern experiences at Llechwedd, Go Below uses caverns that have not been adapted for tourism, giving participants access to underground spaces of extraordinary scale and raw industrial atmosphere: chambers 30–40 metres high, flooded lower levels, and the intact infrastructure of Victorian quarrying preserved exactly as it was abandoned.
A tour lasts 4–5 hours and combines multiple activities: via ferrata on the cavern walls, abseiling into flooded chambers, rope bridges and zip lines across cavern voids, and traverses along exposed ledges. Guides lead groups of typically 6–12 people; all equipment is provided. The minimum age is 10. The experience is physically active throughout — genuine climbing and abseiling rather than a walking tour — and is aimed at participants who want a more demanding underground experience than conventional slate cavern tours provide.
Blaenau Ffestiniog is accessible by the Ffestiniog Railway from Porthmadog (one of the most scenic narrow-gauge journeys in Wales) and by the Conwy Valley Line from Llandudno Junction. Llechwedd Slate Caverns and the Zip World Bounce Below experience are 2 miles away for those wanting a different underground experience on the same visit. Advance booking is essential.
Find it on the map
Frequently asked questions
Go Below operates guided adventure experiences inside the vast Victorian slate caverns of Cwmorthin and Rhiwbach — the abandoned deep-level workings above Blaenau Ffestiniog. The tour lasts approximately 4–5 hours and combines multiple activities: via ferrata (iron-ladder and clip route) on the cavern walls, abseiling into flooded underground chambers, rope bridges and zip lines across cavern spaces, and traverses along exposed ledges with illuminated cavern views stretching hundreds of metres in each direction. The caverns are extraordinarily large — some chambers reach 30–40 metres high — and the industrial archaeology of the Victorian quarrymen's work is visible throughout. All equipment is provided; guides lead groups of typically 6–12 participants.
Llechwedd Slate Caverns (now the Zip World Slate Caverns site) operates commercial underground experiences at a different level of accessibility — the Bounce Below trampoline experience and the cavern tours are designed for a wide range of ages and abilities. Go Below is a more physically demanding, adventure-focused experience in different (unmodified) caverns — the activity involves genuine climbing, abseiling, and via ferrata in spaces that have not been adapted for commercial tourism. Go Below is aimed at people who want a more extreme, less structured underground experience; Llechwedd is better for families with younger children or those wanting a controlled cavern tour. Both operate near Blaenau Ffestiniog but are entirely separate companies on different sites.
The minimum age for Go Below Underground Adventures is 10 years old, with a minimum height requirement (check the Go Below website for current minimum measurements). Children aged 10–15 must be accompanied by a participating adult. The experience involves climbing, abseiling, and via ferrata — participants need to be physically capable of these activities and comfortable with heights and confined spaces. There is no upper age limit provided participants are in good health and able to meet the physical requirements. Go Below recommends good general fitness but does not require specialist climbing or caving experience — the guides teach all the techniques needed on the day.
No — all specialist equipment is provided by Go Below, including helmets, harnesses, wetsuits (for some tours where water is involved), and all climbing and abseiling hardware. Participants should wear or bring warm layers (the caverns maintain a constant cool temperature year-round, regardless of surface weather), sturdy laced footwear, and old clothing that can get wet and dirty. Go Below provides overalls or technical clothing for the activity elements. Long hair should be tied back. Booking is essential and should be made well in advance, particularly for weekend and school holiday dates.
Go Below's base is approximately 1 mile from Blaenau Ffestiniog town centre on the minor road above the town towards Cwmorthin — the postcode LL41 3NB gives the most reliable navigation. There is a free car park at the base. Blaenau Ffestiniog is served by the Ffestiniog Railway (from Porthmadog), the Conwy Valley Line (from Llandudno Junction), and by road on the A470. Arriving by the Ffestiniog Railway (one of the most scenic narrow-gauge journeys in Wales) and walking or taking a taxi to the Go Below base is a popular approach for visitors without cars.