Around half a million people are expected to gather to hear Pope Francis address a huge outdoor Mass on the second day of his historic visit to the Republic.
A total of 500,000 free tickets have been distributed for the event in Dublin's Phoenix Park this afternoon.
The event, which will conclude the Pontiff's weekend trip, will take place after Francis visits the Knock Holy shrine in Co Mayo.
The Pope landed at Knock airport this morning ahead of his visit to the famous Holy shrine.
Four local schools were there to greet the pontiff as he landed in heavy rain. They waved Vatican and Mayo flags.
In August 1879, 15 people said they saw an apparition in Knock of the Virgin Mary, St Joseph, St John the Evangelist and a lamb.
Around 1.5 million people visit the site every year.
The religious engagements come after a day dominated by the bitter legacy of historic scandals linked to church abuse and mistreatment in Ireland.
On Saturday, the Pope met a number of victims of criminality and cruelty inflicted by church members.
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The private engagement in Dublin came hours after Francis expressed "pain and shame" over failures to tackle the scandals.
The world leader of the Catholic Church acknowledged that Irish people had a right to be outraged by its response to the crimes.
Later, inside a Dublin cathedral, he prayed for all victims of clerical sex abuse at a candle perpetually lit in tribute to them.
The Pope's decision to address the dark legacy of abuse in a speech in Dublin Castle drew praise in some quarters, but others criticised Francis for not saying enough or offering a public apology.
With the reverberations of a litany of clerical sex crimes casting a shadow over the first papal visit to the Republic in almost 40 years, Francis acknowledged the gravity of what had happened.
"With regard to the most vulnerable, I cannot fail to acknowledge the grave scandal caused in Ireland by the abuse of young people by members of the church charged with responsibility for their protection and education," he said.
Pope is on his way to shrine pic.twitter.com/u1dz65bJaX— Seamus McKinney (@s1eamus) August 26, 2018
"The failure of ecclesiastical authorities - bishops, religious superiors, priests and others - adequately to address these repellent crimes has rightly given rise to outrage and remains a source of pain and shame for the Catholic community.
"I myself share those sentiments."
Yesterday, the Pope also visited homeless people who receive support from a centre run by the Capuchin Fathers' religious order.
In his Dublin Castle speech, the pontiff also expressed hope that remaining obstacles to reconciliation in Northern Ireland could be overcome.
Ireland has undergone seismic social changes in the four decades since the last papal visit in 1979, when John Paul II was lauded by a nation shaped by its relationship with an all-powerful Catholic Church.
But the church's response to clerical sex abuse scandals, most of which emerged years after John Paul II's visit, have severely damaged trust in the religious institution and seriously weakened its influence on Irish society.
While thousands lined the streets of the capital to catch a glimpse of Francis passing in his famous Popemobile on Saturday afternoon, the crowds were certainly not on the scale witnessed when John Paul II made a similar trip.
And among the well-wishers lining Dublin's streets there were also protesters, who vented their anger at the pontiff as he drove by.