4.6
(59)
3,256
riders
112
rides
Road cycling routes around Llyn Padarn are set within Snowdonia's glacial landscape, characterized by a large lake, surrounding mountains, and historical slate quarries. The area offers varied terrain, from mostly paved lakeside paths to routes with significant elevation gain. Road cyclists can expect a mix of flat sections and challenging climbs, with some routes reaching over 1,000 meters of ascent. The region's geology provides a backdrop of rock formations and ancient woodlands.
Last updated: August 31, 2026
4.7
(7)
209
riders
54.6km
02:57
1,000m
1,000m
Embark on the Pen y Pass and Marchlyn Mawr climb loop from Llanberis, a difficult road cycling route that challenges you with 3296 feet (1004 metres) of elevation gain. This 34.0 miles (54.6 km) journey takes approximately 2 hours and 56 minutes to complete, offering a substantial test of your cycling prowess. As you climb, you will experience impressive mountain scenery, passing by the iconic Yr Wyddfa (Snowdon) and enjoying expansive views across Snowdonia, with glimpses of Anglesey from higher points.
When planning your ride, be aware that the road leading to Marchlyn Mawr Dam is typically closed to cars but remains accessible for bikes. You might need to lift your bike over a gate to continue on this section of the route. Given the steep gradients encountered throughout the loop, equipping your bike with sensible gearing is highly recommended to manage the challenging ascents effectively. This preparation ensures a smoother and more enjoyable experience on the demanding climbs.
This route immerses you in the dramatic Welsh landscape, particularly around the remote Marchlyn Mawr reservoir area, which provides a stunning and isolated backdrop for your ride. The continuous, panoramic vistas you gain from the challenging climbs are a significant reward, showcasing the natural beauty of Eryri National Park. It is a prime example of a route that combines rigorous physical exertion with truly memorable natural surroundings, making it a notable challenge in the region.
5.0
(1)
93
riders
30.6km
01:38
600m
600m
Moderate road ride. Good fitness required. Mostly well-paved surfaces and easy to ride.

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23
riders
25.0km
01:36
600m
600m
Moderate road ride. Good fitness required. Mostly well-paved surfaces and easy to ride.
15
riders
78.0km
03:53
1,030m
1,030m
Hard road ride. Very good fitness required. Mostly well-paved surfaces and easy to ride.
10
riders
21.0km
01:01
240m
240m
Easy road ride. Great for any fitness level. Mostly well-paved surfaces and easy to ride.
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The bridge was probably built in the 17th century and then radically rebuilt and widened in 1795-1796. As with many older bridges, folk tales claimed that the bridge was built by the devil or by the Romans (which an investigation by the National Trust described as "very doubtful"). During the reconstruction, a stone was found with the inscription "W M 1656" scratched on it, suggesting that the bridge is at least that old. Pont Aberglaslyn is located near the downstream end of the Aberglaslyn Pass. Although the location is rocky and the river flows through rapids upstream, it is not far above sea level. (Wikipedia)
7
0
Nice alternative to the bigger roads. Surface is pretty good in the whole.
0
0
Nice steady climb from the Beddgelert side, kicks up in a couple of sections but nothing too stressful. Well worth a visit
0
0
There are over 100 road cycling routes around Llyn Padarn, offering a wide range of options for different skill levels. The komoot community has explored more than 118 routes in the area.
Llyn Padarn offers varied terrain, from mostly paved lakeside paths suitable for leisurely rides to routes with significant elevation gain for more challenging experiences. You'll find a mix of flat sections and climbs, with some routes featuring over 1,000 meters of ascent. The region's glacial landscape provides a backdrop of rock formations and ancient woodlands.
Yes, Llyn Padarn has several easy road cycling routes. For a gentler ride, consider the View of Snowdon – Llanberis Visitor Information Board loop from Llanberis, which is 18.1 km long with moderate elevation, offering scenic views without excessive climbing. The area also features an easy lakeside roll along the shores, providing spectacular views.
For experienced cyclists seeking a challenge, routes like the Pen y Pass and Marchlyn Mawr climb loop from Llanberis offer over 1,000 meters of climbing over 54.6 km. Another demanding option is the Llyn Cwellyn – Pont Aberglaslyn loop from Llanberis, which also features over 1,000 meters of ascent.
Road cycling routes around Llyn Padarn offer views of the magnificent glacial lake itself, the dramatic mountain scenery of Snowdonia, and historical slate quarries. You can also explore the ruins of Dolbadarn Castle, the National Slate Museum, and the iconic 'Lone Tree' on the southwestern shore. The View of Llyn Padarn from Pont Pen-y-Llyn is a notable viewpoint.
Absolutely. The region is rich in history. You can cycle past the ruins of Dolbadarn Castle, a Welsh fortress from the late 12th century. The National Slate Museum and the old Quarrymen's Hospital offer insights into the area's industrial heritage. The Llanberis Lake Railway also runs along the lake's eastern bank, providing scenic views of the historical landscape.
The area is highly rated by the komoot community, with an average score of 4.5 stars from over 40 reviews. Cyclists often praise the stunning glacial lake and Snowdonia mountain views, the historical slate quarry landscapes, and the variety of routes available for all ability levels, from easy lakeside rolls to difficult climbs.
Yes, many routes around Llyn Padarn are designed as loops, allowing you to start and finish in the same location. Examples include the Pen y Pass and Marchlyn Mawr climb loop from Llanberis and the Cromlech Boulders – Mallory's Café loop from Llanberis, providing convenient circular options.
Llanberis, located on the southern banks of Llyn Padarn, serves as a common starting point for many routes and offers various parking options. Padarn Country Park also provides extensive parking facilities, making it a convenient base for exploring the area by bike.
Yes, Llanberis village, a central hub for many routes, has several cafes and pubs. For example, Pete's Eats Cafe is a well-known spot in Llanberis popular with outdoor enthusiasts. You'll find options to refuel and relax before or after your ride.
The spring and autumn months generally offer pleasant conditions for road cycling, with milder temperatures and often clearer skies. Summer can be popular but also busier. Always check local weather forecasts, as conditions in Snowdonia can change rapidly, regardless of the season.
Llanberis, a key village on Llyn Padarn, is accessible by public transport, including bus services, which can help you reach the starting points of many road cycling routes. For detailed information on routes and timetables, it's advisable to check local transport provider websites.


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