The National Treasury Management Agency say they have raised €3bn through the sale of a new 10-year benchmark treasury bond.
The NTMA say there was strong interest in the bond from overseas investors, which matures in 2026.
They say they plan to issue a further €6bn to €10bn of long-term bonds in 2016.
NTMA Director of Funding and Debt Management, Frank O’Connor, said: "This is a strong start to 2016, representing half of our minimum target issuance for the year as a whole and at attractive rates for 10-year funds.
"Today’s transaction, two years to the day from Ireland’s first bond sale since leaving the EU/IMF programme, confirms that investor demand for Irish bonds remains healthy and broad-based."