Swansea officially known as the City and County of Swansea , is a coastal city and county in Wales. It is Wales' second largest city after Cardiff and the twenty-fifth largest city in the UK. Swansea lives within the historic county boundaries of Glamorgan. Situated on the sandy South West Wales coast, the county area includes the Gower Peninsula and the Lliw uplands. it the second most populous local authority area in Wales after Cardiff.