-1406 days -8 hours -47 mins -39 secs

The Snowdon Nantlle Challenge is a strenuous hillwalking adventure that takes place in the heart of Snowdonia National Park. Starting & finishing in the Rhyd Ddu Car Park on the A4085 at the foot of Snowdon’s western slopes, the event consists of two scenic but contrasting loops and involves walking 40 kilometres with 2,500 metres of ascent. We’ll delve deep into Welsh history with our route taking us through the ruins of Glanrafon Slate Quarry, Cwm Dyfor Copper Mine & the Prince of Wales Slate Quarry at the head of Cwm Pennant.

Snowdon Nantlle Challenge

We start with an ascent of Snowdon up the Rhyd Ddu path, then descend the Snowdon Ranger path. On descent, we divert off the track to take in the summits of Moel Cynghorion (674 metres) & Foel Goch (605 metres), before cutting back across to Rhd Ddu on public rights of way to our support vehicle. After refreshments, we head west to take on the Nantlle Ridge, a classic ridge walk, which is exhilarating but not as technical as Crib Goch or Tryfan, and not nearly as exposed. We return to Ryhd Ddu via Cwm Dwyfor.

Once you've booked, you’ll be sent joining instructions, a training plan and kit list. We can also provide advice on local accommodation and other activities.


Distance:     40 km 

Height Gain: 2,500 metres 

Target time: 14 hours

Grade:         VERY HARD / EXTREME

Group Size:  Minimum 4


Self-funding:   £105 per head

Fundraising:   £150 per head plus £30 deposit/registration fee

3D Route Video

Where & when does it start?

Our meeting time is 06.30 am. The walk starts and finishes at the public car park at Rhyd Ddu.

Postcode:        LL54 6TN

What3words:  ///clip.ratio.junction

OS Grid Ref:    SH 571 526

Please note the car park charges are as follows:

  • Up to 4 hours: £3.00
  • Over 4 hours: £6.00

The car park ticket machines accept coins or cards.

Route Map & Altitude Profile

View Route in OS Maps

Loop 1: Snowdon loop

We begin by ascending Snowdon on the Rhyd Ddu path, the quietest and most scenic of the six main routes to the summit, with great views towards Moel Hebog and the hills of Nantlle.

The path initially follows the old track that served the Bwlch Cwm Llan slate quarry, then leaves the track to climb quite steeply over rocky terrain to Llechog ridge. The path then follows the ridge over bare and exposed ground on a narrow and rocky path with steep slopes to the left below, so extreme care is taken on this section.

The path continues to the junction with the south ridge and along to Bwlch Main, with tremendous views over to the Watkin path and Y Lliwedd beyond, before the final climb to the summit.

We descend via the Snowdon Ranger path to Bwlch Cwm Brwynog, where we ascend the fence-line to Moel Cynghorion (674 m). We descend grassy slopes along the fence-line via Bwlch Carreg y Gigran to join the steep path up to Foel Goch (605 m).

We then drop back down to cross the Snowdon Ranger path and pick up a public right of way with old way-markers marking the path. The route passes through the disused Glanrafon Slate Quarry and then over rough ground to meet a newly built path that returns us to Rhyd Ddu, where we can resupply at our support vehicle.

Loop 2: Nantlle Ridge Loop

The Nantlle Ridge scramble from Rhyd Ddu is undoubtedly one of the classic ridge walking routes in Snowdonia.

We begin by heading west across the A4085 to begin a steep ascent of around about 450 metres to our first summit Y Garn (633 m), where the path veers right to the summit. From here, weather permitting, we’ll have great views of the ridge ahead, and of Mynydd Mawr across the valley.

The scrambling then begins, although most of the difficulties can be avoided on the left had side. After the scrambling sections, the route eases off to become an enjoyable & scenic ridge walk.

From Drws y Coed, we follow a grassy ridge and staying on the crest as much as possible, up to the top of Trum y Ddysgl, before we drop back down across a broken, grassy ridge to the obelisk at Mynydd Tal-y-Mignedd.

We descend on a steep, broken path to Bwlch Dros-bern before a rough walk/scramble on an indistinct path to the summit of Craig Cwm Silyn (734 m), which marks the highest point on the Nantlle Ridge.

We continue to Garnedd Goch (700 m), which is really still part of Craig Cwm Silyn & the 3rd highest point on the ridge. The summit is strewn with rock debris and has a trig point and a cairn.

We then backtrack to descend Craig Cwm Silyn and down to Bwlch Dros-bern. From here, we leave the ridge and drop south east on pathless terrain to contour towards the top of an old tramway on an incline that was built for the ill-fated Cwm Dwyfor Copper Mine, which was abandoned in 1878

We follow the incline and rights of way on boggy ground, before the path becomes very obvious and leads up through the Prince of Wales Slate Quarry at the head of Cwm Pennant to Bwlch-y-Ddwy-elor. At its peak, the quarry employed 200 men producing 5,000 tons of slate per annum 

From here, we drop into Beddgelert forest and back onto open hillside where we follow a good footpath for the last couple of kilometres back to our starting point to finish the challenge!

Note: In the map below, it's best to view the route by selecting 'OSM Outdoor' from the dropdown on the top right hand corner of the map, which defaults to 'RWGPS'.

Is it suitable for me?

The Snowdon Nantlle Challenge is very demanding and requires a high level of fitness & commitment and you must be able to walk for up to 14-hours over mountainous terrain. We cover the same distance as the Yorkshire Three Peaks (40 km), but with 800 metres more ascent & some pathless sections. For mixed ability groups we offer the option for less fit participants to complete the Snowdon loop only, which is a great challenge in itself (17.5 km & 1,250 m ascent).

Weather & terrain

The terrain of the Snowdon Nantlle challenge includes well-worn paths, boggy areas (particularly after rain), steep ascents and descents.  Poor weather makes the walk harder and it’s essential that participants have good footwear and adequate outdoor clothing to protect you from the elements. The weather can be unpredictable so be prepared for all conditions! You can check some local weather forecasts below. Snowdonia Mountain Forecast

Water on your walk

We recommend a Water-to-Go filter water bottle for this event - it saves you carrying extra weight on this long hill day and you can fill up safely and drink water from the streams on the route.

What’s included?

  • Mountain Leaders on a 1:10 ratio
  • Support Vehicle at Rhyd Ddu with snacks
  • Access to Vamoos travel app with full event details offline
  • Live GPS tracking & shareable links for family/friends
  • BMC Safety on Mountains book (RRP £6.99)
  • 20% discount for Montane
  • 15% discount for Cotswold Outdoor
  • 15% discount for Open Air
  • 20% discount on Water-to-Go bottles
  • 25% discount on Uphill Athlete training plans

What’s Excluded? 

  • Accommodation (but we can provide advice on options)
  • Transport to/from your accommodation to our event meet point
  • Personal Food & Drink
  • Parking Charges


Your safety is our top priority. Our activities are fully risk assessed and we hold Public Liability Insurance via Lockton LLP. Our leaders carry a mountain first aid kit, an emergency shelter, a fully charged mobile phone & spare battery, spare warm clothing & emergency food and we have two-way radio contact with all of our guides at all times during an event. We also hold a Public Service Vehicle (PSV) Operator Licence.

How to book

Book below by choosing your ticket type. You can choose:

  • Full payment by bank transfer: £105
  • Full payment online (1.5% fee added): £106.58
  • Deposit by bank transfer: £30
  • Deposit online (1.5% fee added): £30.45

If you choose deposit only you'll also be asked if you'd like to pay your balance by raising funds for our social mission.

You'll receive an email acknowledging receipt of your payment/booking. You'll also need to read and agree to both our UK Trip Booking Terms & Conditions and our Participation Agreement & you'll be asked to confirm this during Step 1 when selecting your ticket type.

UK Booking Terms & Conditions Participation Agreement

After booking, you'll receive a second email requiring you to complete our online UK Trip Booking & Medical Declaration Form, which must be completed before we can confirm your booking. Each individual participant must complete this form so if you’re booking on behalf of a group you must ask each member of your group to complete this.

Once you've submitted your UK Trip Booking & Medical Declaration Form, if you have a balance to pay, we'll email you an invoice and this will include our bank details. 

Fundraise for us

Rather than paying your balance, you can alternatively choose to raise funds to support our social mission - with this option, you pay your non-refundable registration fee of £30 when booking and pledge to raise a minimum amount of sponsorship (£150) for our own social projects with disadvantaged young people. We can host fundraising pages directly on our website and you can read some short case studies about our social impact. Read more about fundraising for Inspire Alpine®.

Fundraise for Inspire Alpine® Our Social Impact Set up a fundraising page

What happens if the trip cannot run due to Covid-19?

Your safety is our top priority. Please rest assured that if your event cannot go ahead due to Government-imposed Covid-19 restrictions, we'll offer you a number of options including the chance to:

  • postpone your trip to a later departure of the same event (this year or next)
  • join any other UK event in our portfolio (this year or next)
  • receive a refund of monies paid for the challenge

What if there is no official advice against travel, but I want to cancel?

We respect that you may feel more comfortable staying at home, and not travelling regardless of the official advice. If you choose to cancel, we’ll action your request but where there is no Government advice against travel to at the time of cancellation, our standard cancellation terms will apply.

Donate You can directly support our social mission to close the attainment gap. We support disadvantaged young people to have higher aspirations and feel more confident & resilient. Find out more

Booking for this event has now closed.