The parade comes after Gen Sir Richard Dannatt, the head of the Army, said in September he was concerned that the work carried out by troops was not being acknowledged.
Hundreds of soldiers will be given a heroes' welcome as they march through Cardiff city centre to mark their return home from Iraq.
About 450 soldiers from the 2nd Battalion The Royal Welsh will take part in the parade before a medal presentation at the Millennium Stadium.
The homecoming parade celebrates the end of their tour of duty in Iraq.
Three soldiers from the regiment who lost their lives will also be remembered at the ceremony on Tuesday.
The public are being encouraged to attend the event, which is being funded by the Welsh Assembly Government.
The soldiers, led by the Lucknow Band of the Prince of Wales Division and a Warrior armoured tracked vehicle, will march from Cardiff Castle at 1000 GMT, along St Mary Street to the Millennium Stadium for 1100 GMT.
In front of their families, friends and members of the public, they will be presented with their Iraq medals before enjoying a lunch party on the pitch.
Commanding officer Lt Colonel James Swift said: "We are very lucky to be able to mark our return to Wales in such style and pay a fitting tribute to our fallen comrades."
Three members of the battalion who lost their lives in Iraq - Cpl Paul Joszko, L/Cpl Ryan Francis and Pte Craig Barber - will be honoured at the ceremony.
Two other soldiers who died in Iraq while attached to the Royal Welsh from The Black Watch, 3rd Battalion The Royal Regiment of Scotland - Pte Jamie Kerr and Pte Scott Kennedy - will also be remembered.
Ospreys rugby player Ian Evans, whose sister Lisa has recently returned home from Iraq, welcomed the parade.
"People are putting their lives on the line to protect us and our freedom and I think it's important for people to come along and show their support to the armed forces and the people still serving out there," he said.
The parade comes after Gen Sir Richard Dannatt, the head of the Army, said in September he was concerned that the work carried out by troops was not being acknowledged.
The 2nd Battalion The Royal Welsh, which is based in Lucknow Barracks, Tidworth, in Wiltshire, recruits from the whole of Wales.
