Two adults, a man and a woman aged in their 30s, have been arrested. They are currently detained at a Garda Station in Dublin.
The CRI alert had been issued after the two-year-old had been reported missing from Co Mayo.
A CRI Alert is only issued in the most serious of cases.
Only nine alerts have been issued in the nine years the system has been operating, after launching in Ireland in 2012. This is the second one this year.