The number of Irish people returning to Ireland has increased by 74%, according to the Central Statistics Office (CSO).
Around 21,000 people returned from abroad to live at home between May 2015 and April 2016.
The figures show outward migration has also decreased by nearly 6%.
According to the CSO, the number of immigrants to Ireland in the year ending in April is estimated to have increased by almost 15%, while the number of emigrants has fallen.
It marks a return to net inward migration for Ireland for the first time since 2009 - with 3,100 more people entering than leaving the country.
As a result of the positive net migration and natural population increases, the Irish population is estimated to have been 4.67 million people in April.
Meanwhile, the majority of people emigrating were either at work or a student in the period before they left the country, with 10.4% being unemployed.
57.1% of those leaving the country had a third-level degree or higher qualification, the figures show.
The population estimates differ from the preliminary Census results, which showed a population of 4.76 million.
James Hegarty, CSO statistician, explained that Census uses a "de-facto definition" of population while the annual residence and migration figures are calculated using the "usual residence" concept.
"The de-facto population is the number of persons recorded for each enumeration area on Census night, Sunday, 24 April," he explained. "It includes visitors, tourists and persons who arrive the next morning, who were not enumerated elsewhere.
"The usually resident population includes persons who are usually resident in Ireland plus those usually resident but absent outside the State on Census night. However, it excludes those who are temporarily present in the State, such as visitors and tourists," Mr Hegarty said.
He added that the final Census results will use the 'usual resident' concept.