The couple took part in ceremonies at Dublin's Glasnevin Cemetery.
They paid tribute to Victoria Cross recipients and to the almost 500 people who died in the failed 1916 rebellion against Britain rule.
The couple's four-day visit to the Republic of Ireland and Northern Ireland will end later on Friday.
It will culminate with an event hosted by the British ambassador in Dublin.
The royal couple spoke with Irish politicians on Friday, including Taoiseach (Prime Minister) Enda Kenny and Sinn Féin leader Gerry Adams.
Mr Adams said the prince had commiserated with him over the death of Martin McGuinness, the IRA paramilitary-turned-peacemaker who died in March.
The pair "enjoyed some banter" about which of them was the oldest, added Mr Adams.
On Friday, the prince and the Republic of Ireland's Arts and Heritage Minister Heather Humphreys laid wreaths at the Cross of Sacrifice in Glasnevin Cemetery that honours those killed during the two world wars.
The prince also took part in a ceremony unveiling stones remembering the four Irish soldiers who were awarded Victoria Crosses 100 years ago.
He toured the republican plot in the cemetery and visited the graves of Michael Collins and Éamon de Valera.
After that, he unveiled another wreath at a wall in Glasnevin that remembers all those who died during the Easter Rising in 1916.
On Thursday, Prince Charles tried his hand at hurling at Kilkenny Castle.
He and the Duchess of Cornwall also enjoyed a demonstration of the ancient Irish sport.
Their visit to the Republic of Ireland, which followed a stay in Northern Ireland, was at the request of the British government.
They also visited the Curragh Military Camp, where Irish UN peace-keeping soldiers are trained.
On Thursday morning, the Royals visited a farmers' market in Kilkenny, and they met some of the thousands of people who had lined the streets there.
The couple left Northern Ireland on Wednesday, after Prince Charles opened a garden of remembrance for police officers killed on duty in Northern Ireland.
They also visited the Seamus Heaney Homeplace Centre in Bellaghy, where they met members of the poet's family.

The claim: The UK leaving the European Union would mean cuts to pensions, defence and the NHS.
Reality Check verdict: What, if anything, gets cut if there is a Brexit will be a matter for the government to decide.
"If we restrict our access [to the single market] we will be less well off and that obviously affects what we can spend on our public services," he said.
In the past few days, voters have been warned that leaving the European Union would have severe effects on different areas of public spending.
We've been told both by David Cameron and Labour's Tom Watson that the triple-lock protection on state pensions would be threatened.
We've had Chancellor George Osborne warning that Brexit would lead to between £1bn and £1.5bn of cuts to defence spending.
He pointed out that even if the government stuck to Nato's target of spending 2% of national income on defence, if national income fell, then so would defence spending.
And the prime minister has also warned about spending on the NHS being threatened if the UK left the EU.
Why are they making these warnings? Because economic forecasters have said that leaving the European Union would mean the economy would grow by less than it would have done. That would mean lower tax revenues for the government, which would mean it would struggle to achieve a budget surplus as promised in 2019-20.
What the government chose to do about that would be a question of policy, as David Cameron confirmed, but that has not stopped various groups having a guess.
The Institute for Fiscal Studies predicted the government would decide to delay balancing the budget, bringing in an extra one or two years of austerity at the current rate.
Labour In for Britain said the government would attempt to balance the budget in 2019-20, meaning it would need to make savings of £28bn, which would be divided equally between tax rises, departmental spending cuts and cuts to social security spending.
The National Institute of Economic and Social Research said the government would be trying to save an extra £44bn in 2019-20.
It is also possible that the government could decide not to balance the budget and borrow more instead.
There is a pretty strong consensus that the initial economic shock from a vote to leave the EU would make it harder to achieve a balance in 2019-20, although it could be smaller than some groups have predicted.
Read more: The facts behind claims in the EU debate
The Prince of Wales and the Duchess of Cornwall have honoured Irishmen who fought for Britain and all the people who died in the 1916 Easter Rising.
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On the Andrew Marr Show, David Cameron talked about the effects of leaving the European Union.