Skip to content
View of the Idwal Slabs in Cwm Idwal Valley, Carneddau and Glyderau, Gwynedd, Wales
Cwm Idwal Valley in Snowdonia, Wales | © National Trust Images/Chris Lacey
Wales

Cwm Idwal walk

This moderately strenuous walk offers some of the most dramatic mountainous scenery in the UK at the oldest National Nature Reserve in Wales. Explore beautiful ice-sculpted Cwm Idwal – a bowl-shaped hollow filled with the crystal clear waters of Llyn Idwal, world famous for its rock formations and rare and fragile plant life.

Avoid parking worries by hopping on the bus

At busy periods, the limited parking fills quickly. There are a couple of more sustainable options available with a park and ride from nearby Bethesda. The T10 buses run frequently between Bangor and Corwen as well as Bws Ogwen, a local electric shuttle bus, which runs regularly between Bethesda and Capel Curig. For further details, please see 'Getting there' section.

Total steps: 11

Total steps: 11

Start point

Ogwen Cottage and Ranger Base, grid ref: SH 650603

Step 1

From the Ogwen Cottage Ranger Base, walk in a westerly direction for roughly 93 yd (85m) over the bridge to the Cwm Idwal Visitor Centre building. Steps to the left of the building are the start of the path which ascends steeply at times for approximately 56 yd (50m) through verges of heather, towards the mountain gate.

Step 2

Continue through the gate and over the oak bridge. The oak bridge was replaced in the summer of 2010 using sessile oak sustainably harvested from the nearby National Trust place at Plas Newydd. The bridge provides an excellent opportunity to photograph the peak of Y Garn, with Afon Idwal in the foreground.

Step 3

The footpath meanders in a south-eastern direction for 550yd (500m) before arriving at a junction. Take the right fork towards the west along the more formal stone-surfaced path, and follow for another 550yd (500m) to the lake.

Step 4

At Llyn Idwal (lake) you may choose a clockwise or anti-clockwise route around the nature reserve. This guide takes you on the clockwise option. Before setting off along the eastern lake shore, look left, a few yards above the footpath. Here you'll see a collection of large fractured rocks known as Darwin Idwal Boulders.

Visitors relaxing on rocks known as Darwin Idwal Boulders in Cwm Idwal Valley with Pen yr Ole Wen in the background in Carneddau and Glyderau, Gwynedd, Wales.
Visitors relaxing on the Darwin Idwal Boulders in Cwm Idwal Valley, Gwynedd | © National Trust Images/Chris Lacey

Step 5

The footpath follows the lake shore towards the south for 550yd (500m), until you arrive at a gate through a wall. The wall is there to exclude grazing animals from the nature reserve and to allow the regeneration of natural upland vegetation. Opposite the wall is a small island of rock in the lake. The vegetation growing there gives us a glimpse of how the Cwm may appear in years to come, without the grazing pressure of sheep and cattle.

Step 6

Once through the gate the path begins to rise gently as you climb over mounds of rock debris (moraines) left behind as glaciers retreated from the cwm around 10,000 years ago.

Step 7

You are now approaching the famous Idwal Slabs, a training ground for many pioneering mountaineers including Everest conqueror Edmund Hillary and his Welsh team mate Charles Evans. Roughly 55yd (50m) before the base of Idwal Slabs, follow the path down right towards a level area, using the stepping stones to cross streams. NB: An alternative high level route may be taken at this junction by following the path towards Idwal Slabs and up towards the base of the cliffs above. This route should only be attempted by competent hill-walkers as it involves very rough, steep ground.

Step 8

Look up to your left and you'll see the sheer cliffs which form the headwall of Cwm Idwal, known as Twll Du in Welsh or 'The Devil's Kitchen'.

Step 9

The path rises gradually until you reach the junction of the high level route as it descends through the boulder field. Take a right turn onto this path and walk into an area of heather-clad hummocks.

Step 10

The path climbs gradually through the moraines before descending gently towards the lake shore. Once across the footbridge over Afon Clyd, which tumbles steeply from a hanging valley to your left, go though the gate in the wall. You're now on a shingle beach on the north-west shore of Llyn Idwal. Take a moment to look to the back of the Cwm and absorb the scale of this natural amphitheatre. Try to imagine the area lying beneath a blanket of ice hundreds of metres thick, a mere hundred centuries ago.

Step 11

Follow the lake shore around to the east, until you arrive at a gate through a wall, leading to a slate bridge that crosses Afon Idwal as it drains out of the lake. Once across, you’ll have completed the circular walk around the lake and can retrace your steps to the Ogwen Cottage Ranger Base.

End point

Ogwen Cottage and Ranger Base, grid ref: SH 650603

Trail map

Ordnance survey map of Cwm Idwal walk in Carneddau and Glyderau, Wales
Trail map for Cwm Idwal walk | © Crown copyright and database rights 2012 Ordnance Survey

You made it

Share your experience

More near here

The still waters of Llyn Ogwen, reflecting snowy mountains
Trail
Trail

Llyn Ogwen circular walk 

Escape the crowds of Cwm Idwal and enjoy stunning views on this moderate walk around Llyn Ogwen. Legends say it’s the last resting place of King Arthur’s sword Excalibur.

Activities
Walking
DistanceMiles: 2.9 (km: 4.64)
View of Nant Gwynant from Dinas Emrys, Beddgelert, North Wales
Trail
Trail

The legendary trail of Dinas Emrys 

Enjoy a pleasant walk past waterfalls and through beautiful oak woodland to reach this summit of this legendary hill, where Merlin once trod and where a dragon still sleeps.

Activities
Walking
DistanceMiles: 2.2 (km: 3.52)
Walkers navigating a narrow path beside the Glaslyn river, Craflwyn and Beddgelert, Wales.
Trail
Trail

Aberglaslyn, Llyn Dinas and Cwm Bychan walk 

Explore Aberglaslyn gorge, the waters of Llyn Dinas, the beautiful village of Beddgelert and Cwm Bychan copper mine on this challenging route in Snowdonia.

Activities
Walking
DistanceMiles: 5.7 (km: 9.12)
Bus time table for electric shuttle bus between Bethesda and Capel Curig, Gwynedd

Bws Ogwen shuttle service

Avoid parking issues and travel more sustainably with Bws Ogwen, a local electric bus service running between Bethesda and Capel Curig. Return tickets: Adult - £3, child £2 (under 2s free). Dogs welcome. Wheelchair access available, email cludiant@ogwen.org to arrange beforehand.

Get in touch

National Trust, Bwthyn Ogwen, Nant Ffrancon, Bethesda, Gwynedd, LL57 3LZ

Our partners

Cotswold Outdoor

We’ve partnered with Cotswold Outdoor to help everyone make the most of their time outdoors in the places we care for.

Visit website 

You might also be interested in

A group of people in a hiking group are being guided on a hike by rangers at Marsden Moor, West Yorkshire
Article
Article

Cotswold Outdoor: our exclusive walking partner 

Find out more about the National Trust’s ongoing partnership with Cotswold Outdoor as our exclusive walking partner.

An aerial view of an adult and baby walking a dog along a path at Baggy Point, Devon
Article
Article

Staying safe at National Trust places 

The special places in National Trust care sometimes come with a few risks for visitors, be it coastline or countryside. Find out how to keep safe throughout your visits.

A visitor carrying a backpack and walking along a footpath at Divis and the Black Mountain with stone walls either side, the countryside visible in the background.
Article
Article

Follow the Countryside Code 

Help to look after National Trust places by observing a few simple guidelines during your visit and following the Countryside Code.

Two people out hiking in the snow with a dog are crossing a stile between Tryfan and Glyder Fach, with Nant Ffrancon Pass in the background at Carneddau and Glyderau, Gwynedd.
Activity
Activity

Walking and climbing on Tryfan 

What makes the Tryfan mountain so special? Discover the history of this rugged peak and the challenges it raises for climbers and mountaineers who attempt to conquer it.

Four walkers are hiking up a craggy hill near Pen yr Ole Wen, Carneddau and Glyderau, Gwynedd. There are several huge boulders on the hill and there's a peak visible in the background.
Article
Article

History and legends of Cwm Idwal 

Discover Cwm Idwal’s past, Darwin’s discovery of its creation and the legend of a 12th-century prince, his son and the giant that occupied the land.

A hiker wearing an insulated jacket and a backpack watches the sunset over snowy mountain peaks

Walking 

Explore some of the finest landscapes in our care on coastal paths, accessible trails, woodland walks and everything in between. Find the best places to walk near you.

Walkers enjoying the views from the top of Dinas Emrys, Snowdonia, Wales

Walking in Wales 

Explore wide open landscapes, gentler coastal strolls or energetic hikes for something a little more challenging. We've rounded up some of the best places to walk in Wales.

The exterior of Tal y Braich, Betws y Coed, Gwynedd
Article
Article

Holiday cottages in Eryri (Snowdonia) 

With its towering mountains, deep gorges and pristine lakes, Parc Cenedlaethol Eryri (Snowdonia National Park) is an ideal holiday destination for outdoor enthusiasts and nature lovers alike. Stay at one of our holiday cottages in Eryri (Snowdonia) and explore this special part of Wales.