Eryri Snowdonia Loop (Llanberis)

The Eryri (Snowdonia) loop from Betws-y-Coed toward Caernarfon packs about forty kilometres of Wales’s finest mountain driving into a single day: Nant Gwynant’s lake-floored glacial valley, the high car park at Pen-y-Pass (~359 m), and the cliff-walled descent of the Llanberis Pass on the A4086. Snowdon / Yr Wyddfa (1,085 m) — the highest peak in Wales — sits at the centre of the scenery even when you never leave the van. For classic and low-power campervans this is steep, narrow and busy in summer, but entirely doable if you choose direction carefully, cool the engine on climbs, and treat Pen-y-Pass as a viewpoint rather than an overnight stop.

Start in Betws-y-Coed, the Victorian gateway village at the confluence of rivers in the heart of Eryri National Park. The A498 climbs south-west up Nant Gwynant — a broad U-shaped valley with Llyn Gwynant and Llyn Dinas on the floor and steep cwms above. The road is quieter and gentler than the Llanberis side; Pen y Gwryd hotel at the head of the valley was the base for the 1953 British Everest expedition and still displays memorabilia. At Pen-y-Pass the Pyg Track and Miners’ Track begin; the car park fills early on peak summer days — arrive before 8am or skip parking and continue through.

The A4086 descent through Llanberis Pass is the dramatic half: volcanic rock walls, waterfall spray on the tarmac even in dry weather, and remnants of copper workings on the valley sides. Use low gears and engine braking; the road is public and well used by coaches and walkers’ shuttles. Llanberis at the foot grew on slate: the National Slate Museum in the restored Dinorwig quarry workshops is free to enter (parking nearby is charged) and is one of the best industrial heritage stops in Wales. Dolbadarn Castle’s lonely keep sits above Llyn Padarn if you want a short Cadw stop before continuing.

The final leg to Caernarfon ends at Edward I’s great castle — a UNESCO World Heritage Site begun in the 1280s and still one of Europe’s most impressive medieval fortresses. Park in town waterfront or edge-of-town car parks rather than forcing a long van through the tightest streets. Wild camping without landowner permission is generally illegal in Eryri; use campsites around Llanberis, Betws-y-Coed or official motorhome areas near Caernarfon. May–June and September give longer light with fewer queues; August bank holidays jam Pen-y-Pass. Anti-clockwise (Nant Gwynant up, Llanberis down) is the gentler climb for low-power vans. Build the day around cooling stops and early starts rather than summit ambition from the van. Pen-y-Pass is a trailhead, not a campsite — toilets and a café may be available in season, but overnighting is not appropriate and enforcement is common. If you want Yr Wyddfa’s summit without the scramble, the Snowdon Mountain Railway from Llanberis is the established alternative when weather and bookings allow. Carry cash or a card for Padarn Country Park parking beside the slate museum, and allow at least ninety minutes inside the workshops. On wet days the Llanberis Pass tarmac can be polished with spray; leave extra following distance behind coaches. Classic and low-power campervans thrive here when you treat forty kilometres as a full cultural day — lakes, slate, castle — instead of a mountain sprint between Instagram pull-offs.