Pen y Pass is one of the most classic road cycling challenges in North Wales. It is certainly an impressive spot with stunning views across the upland landscape. On the western side of the col is the Llanberis Pass, a dramatic, mountain valley littered with crags and boulders, while to the east is the broad spread of Dyffryn Mymbyr and the beautiful, wooded Nant Gwynant.
The route works well in either direction. From Nant Peris it’s a fairly tough climb with 250m height gain, although at no point is it desperate. The steepest bit comes at around 500m before Pen y Pass. This section is great for ‘out of the saddle’ efforts. The long and fast descent back down the same hill is also one of the best in Snowdonia. (Caution should be applied with regard to grip on the corners and oncoming traffic.)
The col can also be approached from the east side with a fairly long climb up from Nant Gwynant, followed by a short climb from Pen y Gwryd up to Pen y Pass, passing the exposed corner at Bwlch y Gwyddiel. This gives around 280m of height gain from Llyn Gwynant.
A splendid clockwise 51km loop route can be done by linking Llanberis, Nant Peris, Pen y Pass, Pen y Gwryd, Nant Gwynant, Beddgelert, Rhyd Ddu, Waunfawr and Llanrug to finish back at Llanberis. Another loop of a similarly length and quality can be done from Llanberis round to Bethesda, up to Ogwen Cottage, along to Capel Curig then back to Pen y Gwryd and over Pen y Pass.
During the winter months Pen y Pass is occasionally blocked with snow.
There are various starting points, depending on your intended route, but the main car park in Nant Peris is a good option for a quick run up and down.