Rugby fans face extra travel disruption as Wales face France in their Six Nations clash due to flooding and landslides caused by Storm Dennis.
The line between Pontypridd and Aberdare will be closed after the bad weather last weekend, but several lines have been reopened.
A full city centre road closure is in effect from 13:15 GMT until 19:45 on Saturday, after a 16:45 kick-off.
Cardiff Council advised rail passengers to leave plenty of time for journeys.
About 75,000 fans are expected at the Principality Stadium as Wales look to recover from defeat in Ireland and derail France's hopes of claiming a Grand Slam.
In addition to scheduled road closures, Newport Road in the Rumney area was shut on Saturday from about 08:50, after a serious three-car collision at the bottom of Rumney Hill, but has since reopened.
And those travelling from parts of the south Wales valleys are facing potential disruption.
The line between Cardiff and Aberdare is shut due to track damage between Pontypridd, Rhondda Cynon Taff and Aberdare.
Rail replacement bus services will be operated between closed stations.
But the line between Abergavenny and Hereford, leading to north Wales and the midlands, which has been closed all week due to flooding, reopened at about 04:00.
Bethan Jelfs, from Transport for Wales, said: "The situation is improving but with further warnings of heavy rain from Friday through to Saturday we strongly advise customers to watch the weather and check the TfW app and website for any changes to their route into Cardiff Wales v France Six Nations rugby international in Cardiff on Saturday 22 February.
"Storm Dennis caused significant damage to the rail network and highways. Most of this has now been repaired thanks to the hard work of all our people in extreme weather conditions.
"We would like to thank customers in advance for their patience and understanding."
Duke Street, Castle St, High Street, St Mary Street, Caroline Street, Wood Street, Central Square, Westgate Street, Quay Street, Guildhall Place, Golate, Park Street, Havelock Street and Scott Road will all be closed in their entireties, while parts of Kingsway, Cowbridge Road East and Tudor Street will also be closed.