In the 2015 General Election, the Tories won 11 seats, gaining three - making it the best Conservative performance in Wales since 1983.
The Swansea constituencies, all currently Labour seats, are due to report at 03:00am. Also declaring at 03:00am is Wales' largest constituency, Brecon & Radnorshire, which was won by the Tories from the Lib Dems in the last election.
Cardiff is split into Cardiff Central, which was taken from the Lib Dems by Labour last time round, Cardiff South & Penarth and Cardiff West, also Labour seats, and Cardiff North, held by the Conservatives. All of the city's constituencies are set to declare at 06:00am on Friday 9 June.
General Election 2015: Have a look at how the UK voted in the last election