The National Treasury Management Agency has raised €4 billion from a syndicated sale of a new 2050 bond today, beating earlier expectations of €3 billion.
Demand for the bonds when the books closed was in excess of €18 billion, comprised over 325 individual accounts.
The yield was 1.53% and over 98% was taken up by overseas investors.
"Today's transaction demonstrates that investor appetite for our bonds continues to be strong and broadly based," said NTMA Director of Funding and Debt Management, Frank O’Connor.
"We have now exceeded 50% of the mid-point of our target of €14 - €18 billion for the year."
"We took advantage of favourable market conditions to execute our second syndicated transaction of 2019 and to continue our strategy of prefunding to meet future redemptions."
"Our strong cash balances leave us well placed to meet upcoming maturities in June and October and enhance our ability to borrow on attractive terms."
The syndicated deal replaces a bond auction that had been scheduled for today after Cyprus's recent first 30-year bond sale was overloaded with orders.
The use of syndication broadens the investor base for the bonds, allowing smaller euro zone countries to compete with the larger countries that can attract demand because of their benchmark status.
Using banks to find demand should also help secure more aggressive pricing and ensure liquid trading.
High demand for long maturities - with Ireland an active seller in recent years - shows how much Europe's bond market is adjusting to expectations of persistently low interest rates and central bank stimulus.
Barclays, BNP Paribas, Cantor Fitzgerald Ireland Ltd, Danske Bank, Deutsche Bank and Goldman Sachs are joint lead managers for the transaction.
Meanwhile, Irish and Spanish borrowing costs remained close to record lows today ahead of the bond sales that could well cement their move away from the "periphery".
This is a phrase used to describe the lower-rated and more volatile euro zone bond markets.
Even though political issues are clouding the outlook for both countries, with Spanish coalition talks rumbling on and an uncertain Brexit outcome hanging over Ireland, their debt has been in heavy demand in recent weeks.
Benchmark Irish 10-year bond yields were close to their lowest since December 2017 at 0.495% while Spanish 10-year yields were near a two and a half year low at 0.96%.
Ireland has had a Single A rating from all three of the main credit ratings agencies for a while now, and Spain has more recently been upgraded into Single A status by two out of the three; S&P Global and Fitch.
This represents an improvement from the days of the euro zone debt crisis of 2010-2012, when both countries needed euro zone bailouts and Spain teetered on the edge of a junk rating and Ireland dropped into the Triple B ratings bucket.
An inconclusive Spanish election earlier this month and questions over the Spanish deficit and the separatist issue in Catalonia have not been a barrier to investor demand for Spanish government debt.