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Lon Las Ogwen Bangor, Bethesda to Ogwen

By Dave Roberts   

on February 24, 2019    4.67/5 (3)

Posted as a walk in – Europe, Snowdonia National Park, Wales

Lon Las Ogwen Bangor, Bethesda to Ogwen

Further Details

Route Summary:

Lon Las Ogwen is a spectacular cycle track from the City of Bangor into the heart of Snowdonia National Park.

Route Start Location: Bangor to Ogwen

17.46 km 500 m 3 hours

Calculate the time using Naismith’s Rule and factor in your own pace.

Activivity Type: Hard Walk, Mountain Biking, Trail or Fell Runs

Summits and Places on this Route


Facilities can be found off route in Bangor and Bethesda. There’s a visitor centre and the trusty hatch serving snacks at the turn arounsd point at Ogwen, as well as toilets.


Remember that we cannot outline every single hazard on a walk – it’s up to you to be safe and competent. Read up on Mountain Safety , Navigation and what equipment you’ll need.

Parking :

Limited parking at the start in Bangor, but there’s more parking near the Hirael seafront.

Public Transport:

There’s a regular bus service between Bangor and Bethesda, and an irregular one between Bethesda and Ogwen

Traveline for UK Public Transport

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Weather Forecast:

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Lon Las Ogwen Bangor, Bethesda to Ogwen Ordnance Survey Map and GPX File Download

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Lon Las Ogwen Bangor, Bethesda to Ogwen

The Lon Las Ogwen cycle track is a largely traffic free trail that takes you between Bangor and Ogwen, along disused railways and quiet lanes. It connects to the NCN 5 National Cycle route in Bangor, which can be reached largely traffic free from Caernarfon. Lon Ogwen has been designated the National Route 82.

The trail involves a significant amount of ascent, with the final pull up to Ogwen particularly tough if you’re not used to cycling hills. Despite that, this is probably the most spectacularly situated cycleway in Wales with the final section up to Ogwen surrounded by the high peaks of the Carneddau and Glyderau. Another highlight is the newly opened tunnel at Tregarth. Prior this being opened, sections of the track were along roads and the trail was confusing to follow. The Lon Las Ogwen is now a world class trail.

The route can also be extended by the adventurous  to reach Capel Curig along the old coach road. Thankfully it’s mainly downhill to Capel Curig, although the track can be heavy going. That section has been described in reverse on our Nant Ffrancon Trail Run, with the information being relevant if you’re in trail runners or on two wheels.

The Route

The Lon Las Ogwen can be split into four distinct sections. Some are more established than others, with one section requiring the bikes to be pushed

1 – Porth Penrhyn (Bangor) to Tregarth. The first section of the Lon Las Ogwen has been open since the 1980s, and is a popular track for locals. Starting at Porth Penrhyn, the track is easy to follow for this section along the Afon Cegin. There’s very little thinking required on this section, with only a minor road to cross at Glasinfryn, and a main road by bridge further on. It follows the Penrhyn quarry former railway for the initial section before joining the former Bethesda Branch line, and swaps back and forth between them a few times. Once you reach Tregarth, the off road path ends.

2 At Tregarth, the Lon Las Ogwen will join the road. This isn’t a pleasant section, with the road being narrow, no pavement and busier than expected as this is the main junction in Tregarth. Turn right onto the road and take the first left and an immediate right turn towards the play area. The connection section of the railway has long been reclaimed and filled in, you can see the former bridge behind the nursery that nestles below the road. This section really needs to be made off-road to make this trail family friendly.

3 From the play area  the Lon Las Ogwen continues to Bethesda via the newly opened Tynal Tywyll (Dark Tunnel), officially called Twnnel Penddinas but always Tynal Tywyll to generations of locals. This initial section is on a high embankment so make sure any little ones don’t go veering off the track (or maybe it’s just ours who like cycling full pelt into random undergrowth?) The highlight of the section is the recently opened Tynal Tywyll, a lit former railway tunnel recently opened to the public.

4 From Tynal Tywyll the track continues, a little haphazardly in places as it crosses some lanes and passes through fields with up to 3 gates in some places! The views towards the mountains begin to show themselves on this section, and while impressive now they get even better as you continue. Pure cyclists can continue on to Bethesda and work their way across the Afon Ogwen further up to rejoin the cycletrack. The Lon Las Owen reaches a footbridge at SH 616 667 where the track turns right and steeply up a path. You’ll need to push your bike up here!

5 The track evens out, then follows the B road for a short distance before pulling uphill to the right towards the workshops to join the Penrhyn quarry former railway. The Lon Las Ogwen again becomes a proper cycle track, and this section continues with the Afon Ogwen to one side, slate tips to the other and the mountains of Snowdonia enticing you ahead.

6 The cycle track finishes at a minor road at SH 6299 6368, and you’re fully in the mountains now. The climbing has been reasonably steady up to now, but the next section is much tougher. This is a god point to turn around if the climb ahead is too strenuous. There’s very little traffic on the lane, but it can be narrow and has occasional drops to the valley which need care. Thankfully, the impressive views give you plenty of excuse to stop for a breather!

Finally the route finishes at Ogwen, where you’ll deserve a snack from the refreshment kiosk. While you’ll need to repeat the route in reverse, at least it’s now downhill! You can also continue to Capel Curig on the old coach road, with the forestry tracks of the Gwydr Forest also within reach.

Dave Roberts founded Walk Eryri in 2004, with the aim of providing routes that are off the beaten track. Walk Eryri is now part of Mud and Routes which continues to provide more off beat routes and walks in Snowdonia and beyond. Dave has been exploring the hills of Eryri for over thirty years, and is a qualified Mountain Leader. Dave also established Walk up Snowdon, Walk up Scafell Pike and Walk up Ben Nevis just to mention a few.
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