North Wales has climbs for very different days out, from the coast at Llandudno to the mountain roads of Eryri, also known as Snowdonia. I went to university in Bangor and love exploring the area by bike. These are seven favourites from those rides, with the original profiles and photographs retained to show the approaches described.
The profiles refer to particular start and finish points, not every possible approach. Gradients and distance will differ if you begin elsewhere. Plan the whole ride, check the weather and current access, and leave enough energy for the roads between climbs.
| Climb | Character | Planning point |
| Pen-y-Pass | Sustained mountain-road climbing | Expect traffic on the A4086. |
| Marchlyn Mawr via Fachwen | Steep lanes followed by a reservoir road | Check access before continuing onto the operational road. |
| Nant Gwynant | Longer, varied approach to Pen-y-Pass | Allow for junctions and visitor traffic. |
| Drws y Coed | Shorter ramps through the Nantlle valley | Control speed on the descent towards Rhyd Ddu. |
| Sychnant Pass | Compact coastal foothill climb | Works with a Conwy and Llandudno route. |
| Great Orme | Exposed headland road | Distinguish Marine Drive from the summit roads. |
| Stwlan Dam | Steep reservoir-road hairpins | Check access and respect operational restrictions. |
Favourite cycling climbs in North Wales
1 – Pen-y-Pass from Nant Peris
First off, a classic. Pen-y-Pass is the climb out of Llanberis on the A4086 up to the Pen-y-Pass lodge where several walking routes to the summit of Snowdon start from. Check current café opening before relying on a stop at the pass.
The climb is a reasonably long one at 2.4 miles. There’s some lumps coming out of Llanberis but the climbing doesn’t really start until you’re through the village of Nant Peris. The climb from this point averages 6% to the top with a maximum grade of 10.2%. Early on, the grade sits at around 3-4%, a nice early warm-up for what’s about to come.
There’s a little dig just before the 1-mile mark but then it returns to an easy 2%. You’re now entering the 2nd part of the climb where it sits bang on that 6% average for the next mile. You come round a bend over a river stream and you can just about see the lodge up ahead. You can also see all of the road that you’ve got ahead of you.
The final section sees you battling 9-10% until the summit. It starts when the road refuses to stay in a straight line. Not exactly S-bends but there’s a definitely wiggle back and forth. Give it a final blast up to the youth hostel and you’re done!
The Tour of Britain descended the Llanberis Pass in 2013 and climbed up the same pass in 2015’s race.
2 – Marchlyn Mawr (the long version)
aka Electric Mountain
The Marchlyn Mawr climb in itself is a stiff climb up to a reservoir with awesome views. This version tacks on the Fachwen climb to the start of it and has 3 distinct sections.
The first section starts going over the bridge over the Afon Rhythallt, just off the A4244 west of Llanberis. A nice flat bit by the lake to start, the first ramp takes you up through the woods at about 10%. You get to rest through the scattered houses before hitting the tough end part. A long 10% grade winds up to 25% right at the junction in Dinorwig. Make sure you’ve come with sensible gearing!
There’s now a flat part after turning right but make sure to change down for the next left turn as there’s a short dig before it flattens out for your mid-climb breather. Good things come to an end though, take the next right for a solid ramp up to the gate. This leads towards an operational reservoir access road. Check the signs and current cycling access before continuing; a gap or pedestrian gate is not proof of permission, and a closure is a reason to turn back.
Here’s where the Marchlyn Mawr climb starts. A slow wind-up at around 7% turns the wick up to 12% as you approach the junction. Keep going straight through! The right turn is another climb you can do though. You start your way up to the lazy long hairpins which will take you to the top. If you’re with people, you can see them going back and forth ahead of you at this point.
The endpoint is pretty clear, the road runs out and there’s a big gate in front of the tunnel into the mountain. You can now see the Marchlyn Mawr reservoir and the awesome views out across all of Snowdonia and Anglesey.
3 – Nant Gwynant
Nant Gwynant is a lovely long climb that is never steep for too long and gives amazing vistas of the heart of Snowdonia. Heading north out of Beddgelert the road takes you up to Pen-y-Pass from the reverse side (with a left turn at the Roman Camp junction). You get to ride past the long lake at the bottom which gives the climb its name.
The early stages are just a tiny fraction of a gradient and are tree-covered. A couple of steeper ramps followed by sections where the gradient backs off again helps you get some elevation. Once the trees start thinning out, it’s worth a look over your left shoulder to see the lake in all its glory on the valley floor. There’s even a perfectly placed lay-by if you want to stop and snap a photo. The steepest ramp is around 1.5 miles in but once done with, everything else is easier.
Near the junction for Pen-y-Pass, expect visitor traffic and vehicles turning or stopping. Do not treat informal roadside parking as an approved place to leave a car. The gradient eases before the left turn onto the final approach, but keep your attention on the junction.
The first part should take off the speed you carried through the corner but then flattens out nicely. As you start approaching the right-hander with only the stone wall on the outside separating you from the abyss below, it gets steeper again. You can see the lodge though as soon as you make the corner which helps give you a target to full-gas it to the finish.
4 – Nantlle
aka Drws y Coed
The Nantlle climb takes you up the pass to see the Nantlle ridge. Taking the B4418 out of Penygroes towards Talysarn you progress slowly up the valley until the proper climb appears. There’s an early rise past a farm to really warm up those legs. It’s a short steep affair to kill your speed but eases off again afterwards. You can see the rocky outcrop slice ahead of you too, that’s where the road winds itself to the top.
Take it easy on the flat and take in the views of the rocky ridges up above you on both sides now. An easy left-hander signals the start of the climb proper with a near double-digit gradient ramp up through the right-hand bend coming up. Once again you get a rest as the climb flattens itself out for a bit.
Make sure you’ve not maxed yourself out before the final blast to the summit. The climb reaches its steepest point just after the next corner but the end is just there. There’s now a fun descent to Rhyd Ddu with postcard views of the lake and valley down to Beddgelert. If you follow the road to Beddgelert, you can do another of the cycling climbs in North Wales by going up Nant Gwynant.
5 – Sychnant Pass
There are two approaches to the Sychnant Pass, the one I like is on the Conway Old Road out of Penmaenmawr as I usually approach it from the west. There’s a little pre-ramp not on the above profile but you can take the downhill from it to the start of the climb in the village of Capelulo.
A swing to the left where the cafes and restaurants are is the start of the climb and where the yellow/orange segments start in the above image. You very quickly pass the junction where the alternative approach joins onto the climb. At this point, the stone wall on the left starts and the climb really ramps up. It never gets steeper than this thankfully but just goes on and on.
You come out of the trees, the wall stops and you can see the top of the pass for the first time. The rocky hills around you somehow often look like a deep purple colour. You can look behind you on the right-hander for a glimpse of the sea. You’ll have come from near enough sea-level if you’ve ridden from the west.
The stone wall reappears and you’re on the last long steep ramp. There’s a lay-by at what looks like the top and more often than not, there’s an ice-cream van parked up too. There’ll often be walkers (or sheep) milling around the road to avoid and put on the hill climb poker face for. Catch a last glimpse of the sea behind as you head into the double-walled section with the summit proper just round the corner.
If you want to join up some of the cycling climbs in North Wales, the Sychnant Pass leads into Conwy. From there you can continue towards Llandudno for the Great Orme, allowing for the extra distance and town traffic.
6 – Great Orme
The Great Orme rises above Llandudno, with Marine Drive running around the headland. That coastal road is different from climbing to the summit. The first part of Marine Drive is one-way from the North Shore end, so follow the signed direction and check for closures before setting off.
The exposed road provides sea views, but do not assume the toll makes traffic light or slow. Allow for vehicles, pedestrians and wind around the headland. The Rest and Be Thankful café is on Marine Drive, not the summit; check opening if you are planning your stop around it.
The full Great Orme cycling guide explains the route choices in more detail.
7 – Stwlan Dam
Stwlan Dam is one of my favourite climbs in North Wales. The reservoir road and its tightly packed hairpins give it a very different feel from the main-road passes. The original photograph below shows why this is such a memorable place to ride.
It is also an operational access road. Do not assume a gate means traffic-free cycling is permitted, and do not bypass a closure. Check current signs and access arrangements before riding, yield to authorised vehicles and turn back when access is restricted.
Read the Stwlan Dam guide for the climb, and compare it with Marchlyn Mawr when deciding which reservoir road fits your plans.
Linking the climbs into a ride
Pen-y-Pass and Nant Gwynant can form part of a mountain loop, while Sychnant and the Great Orme work better as a coastal pairing. Stwlan Dam is a separate outing from the Llanberis climbs unless you deliberately plan a much longer day. Avoid treating all seven as a single ready-made route.
Carry low enough gearing for the steepest lanes, a layer for descents, food and a way to navigate if mobile reception drops. For another North Wales option, the Horseshoe Pass guide covers the climb near Llangollen. Choose the area and route length first, then add climbs that suit the time and conditions.
