Mobile phone reception varies greatly on Snowdon (Yr Wyddfa), and it’s important to appreciate that a mobile signal cannot be relied on. Also, remember that cold conditions considerably reduce normal battery life so it’s not a bad idea to take a spare power pack too.
Reception is best on the Llanberis Path because it can pick up the transmitter in Llanberis, and there is a good 4G signal at the summit.
Signal is intermittent on the Pyg Track and Miners’ Track, and there is currently none at Pen y Pass.
The worst signal is on the south and west sides of the mountain, affecting the Watkin Path, Rhyd Ddu Path and Snowdon Ranger Path. (Where you can get a signal, EE is best as that is currently the only transmitter in Beddgelert.)
(A new 4G mast has been erected behind Rhyd Ddu station, the aim being to improve connectivity for the emergency services and allow 999 calls on this western side of the mountain. It’s not clear whether it will ultimately be available for normal calls; such a move would considerably improve communications on both the Rhyd Ddu Path and Snowdon Ranger Path.)
However, where the signal is not good enough to make a phone call, a text or WhatsApp message will often not take too long to get through.
The only car parks that currently have a phone signal are in Llanberis. The car park at Pen y Pass, whilst it has no signal, has free WiFi near the building.
If you are planning on phoning for a taxi, you should bear the above in mind.