Llandudno Junction (Welsh: Cyffordd Llandudno), once known as Tremarl, is a town in the county borough of Conwy, Wales. It is part of the ancient parish of Llangystennin, and it is located south of Llandudno. It adjoins Deganwy and is to the east of the walled town of Conwy, which is on the opposite side of the River Conwy. The population is 6,722 (2011) and is part of the community of Conwy, and comprises the wards of Marl and Pensarn (Llandudno Junction). The built-up area of Llandudno Junction and Deganwy had a population of 10,658.
The town grew up around Llandudno Junction railway station, which is a junction between the Crewe-Holyhead line and the Llandudno-Blaenau Ffestiniog line. There are through trains from Manchester to Llandudno, but passengers travelling from London, Cardiff, or Holyhead to Llandudno usually have to change trains at Llandudno Junction.
Llandudno Junction, in addition to its passenger interchange, had a major steam locomotive servicing depot and extensive goods facilities. This railway depot was called 6G, and a new section of the A546 (carrying the name “Ffordd 6G Road”) now crosses the site. The site of the depot and goods yard has been redeveloped, now accommodating a business park, fast food outlets, a leisure centre, a Cineworld multiplex cinema, and a Tesco supermarket. Llandudno Junction has recently added a Lidl store, too.