The Taoiseach and the first ministers of Scotland and Wales were among those attending the meeting
The relationship between Ireland and the United Kingdom needs to stay strong in the wake of the Brexit vote.
That is according to members of the British-Irish Council, who met earlier today to discuss the fallout from the vote.
Taoiseach Enda Kenny, Northern Ireland's First Minister Arlene Foster and the First Minister of Scotland Nicola Sturgeon all attended.
The new Secretary of State for Northern Ireland, James Brokenshire, also travelled to Cardiff for the meeting.
The Welsh First Minister Carwyn Jones warned that things cannot stay the same after the pivotal decision to leave the EU.
In a statement after the meeting, the Council noted: "There are a number of priority areas where implications arise, in particular: the economy and trade, the Common Travel Area, relations with the EU and the status of all citizens affected by the change."
They also said "that the process for implementing the referendum outcome would become clearer in the coming months".
The leaders also "reiterated their commitment to facilitating harmonious and mutually beneficial relationships among the people of these islands".
Another meeting of the British-Irish Council will take place in November.
The British-Irish Council was established under the Good Friday Agreement, and today met for the 27th time since 1999.
John McGrane is CEO of British and Irish Chamber of Commerce spoke to Newstalk Breakfast about the talks.
He explained: "The British-Irish Council is one of the valuable, if you'd like, unofficial quangos of the post Peace Process domain.
"It's one of the valuable back channels and offline channels where people can think about the business to be done in a more productive way".
Gina Quinn is from the Dublin Chamber of Commerce, and suggests these are very important discussions.
"They're part of a dialogue, and part of us understanding what solution we are going to get to the current dilemma."
She added that Britain's vote to leave the EU "has left us all with an enormous need for more communication, more talks".
Meanwhile, a House of Lords report shows that the UK's exit from the EU is the most complex and important for the country task since World War 2.
It comes as Boris Johnson says the US is beginning to see the benefits of the UK leaving the European Union.
He has been meeting with officials in Washington - and last week US secretary of state John Kerry held talks with the new British foreign secretary in London.
Mr Johnson says the American government is becoming more optimistic.
"[Mr Kerry] and the Americans see this as an opportunity for the United Kingdom to have more of a role on the world stage - and I really agree with him," he explained.