The Taoiseach is in Portugal for discussions with the country's Prime Minister.
The trip is one of many Bertie Ahern will be making to European capitals over the next 15 months as Ireland prepares to host the EU Presidency next year.
Today the Taoiseach will also launch a new airline service between Lisbon and Dublin.
Later he will hold talks with the Prime Minister and President of Portugal where a constitution for Europe is expected to be discussed.
Mr Ahern will return to Dublin later this evening.