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Bike touring routes & trails

Marchlyn Mawr Reservoir – Llanberis Tunnel loop from Llanberis

Bike touring routes & trails

Marchlyn Mawr Reservoir – Llanberis Tunnel loop from Llanberis

Hard

5.0

(1)

16

riders

Marchlyn Mawr Reservoir – Llanberis Tunnel loop from Llanberis

01:57

25.0km

660m

Cycling

Hard bike ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels. The starting point of the route is accessible with public transport.

Last updated: August 27, 2026

Tips

Your route passes through a protected area

Please check local regulations for:

Parc Cenedlaethol Eryri

Waypoints

A

Start point

Bus stop

760 m

Llyn Padarn

Lake

2

2.93 km

View of Llyn Padarn from Pont Pen-y-Llyn

Highlight • Viewpoint

On a clear day, from this end of Llyn Padarn you’ll get an enticing view of Snowdon and other peaks.
Its absolutely stunning and well worth the ride.

Tip by

3

4.82 km

Steep Descent

Highlight • Trail

4

11.0 km

Marchlyn Mawr Reservoir

Highlight • Lake

Marchlyn Mawr reservoir is a high level lake in Snowdonia behind Elidir Fawr mountain. It is used as the high level water source for Dinorwig electric power station, a closed-loop pumped storage hydroelectric generating facility.

Tip by

5

23.1 km

Llanberis Tunnel

Highlight • Structure

Great bike path with a small section through the hill for a change!

Tip by

B

25.0 km

End point

Bus stop

Way Types & Surfaces

Way Types

19.7 km

3.77 km

1.26 km

263 m

Surfaces

16.2 km

8.68 km

114 m

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Elevation

Nothing selected – click and drag below to see the stats for a specific part of the route.

Highest point (630 m)

Lowest point (100 m)

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Weather

Powered by Foreca

Friday 23 October

15°C

6°C

98 %

Additional weather tips

It’s set to rain on your activity. Pack a waterproof jacket.

to get more detailed weather forecasts along your route

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