Charles and Camilla will travel to the Welsh capital on Friday, having already toured parts of Scotland and Northern Ireland.
It will be the first time the new King has set foot on Welsh soil since ascending to the throne last week.
He has bestowed his former title, the Prince of Wales, on his son William, whose wife, Kate, is now the Princess of Wales.
The royal couple’s first stop will be at Llandaff Cathedral, where they will be greeted by the Lord Lieutenant of South Glamorgan, before taking part in a Service of Prayer and Reflection for the Life of the Queen, which will be led by the Dean.
The Archbishop of Wales, Bishop of Bangor Andy John, will give the address and First Minister Mark Drakeford will give a reading.
After the service, Charles and Camilla will greet schoolchildren and members of the local community who have gathered to see them.
The King and Queen Consort will then be presented with a Motion of Condolence inside the Senedd’s Siambr, its main debating chamber, in Cardiff Bay.
They will have a chance to read condolence messages from members, including the leaders of all the main political parties, who took part in a special session on Sunday when the Senedd was recalled.
The King is expected to then share a private audience with Mr Drakeford and the Senedd’s presiding officer, Elin Jones, at Cardiff Castle.
He and Camilla will then have a reception with guests from local organisations, charities and members of faith communities.
Wales will be the last country in the United Kingdom Charles will visit before the Queen’s state funeral on Monday (September 19).