Ireland's ambassador in London, Dan Mulhall, is to become ambassador to the United States as part of a rotation in the senior ranks at the Department of Foreign Affairs.
Mr Mulhall, who succeeds the retiring Anne Anderson, will be replaced in London by Adrian O'Neill, a former secretary general at Áras an Uachtaráin and current second secretary at the department. With Brexit set to dominate the Irish diplomatic agenda in the coming years, Mr O'Neill will move into a key position at a pivotal moment in Anglo-Irish relations.
The latest heads of mission nominations, which were approved by Government on Tuesday, include personnel changes in key capitals in Europe, Asia and Africa.
The current ambassador to France, Geraldine Byrne Nason, will become Ireland's permanent representative to the United Nations in New York and will lead the State's campaign for a seat on the UN security council in 2020. She will succeed David Donoghue, who is retiring.
David Cooney, a former secretary general at Iveagh House and the current ambassador to Spain, will become ambassador to Italy, replacing Bobby McDonagh, who is returning to Dublin.
Another of the department's most senior figures, Paul Kavanagh, who is currently ambassador to China, will take on the position of ambassador to the United Arab Emirates as well as Afghanistan, Kuwait and Qatar.
Patricia O'Brien, currently permanent representative to the UN in Geneva, is to replace Ms Byrne Nason as ambassador to France, while the head of Irish Aid, Michael Gaffey, will take on the senior position at the UN in Geneva.
The next ambassador to China will be Eoin O'Leary, who has been based at the department's Dublin headquarters in recent years. Kevin Dowling, until recently chargé d'affaires at the Irish embassy in Vienna, will replace the retiring Philip McDonagh as permanent representative to the Organisation for Security and Cooperation in Europe (OSCE) in the same city.
The other nominees for ambassadorial roles are Síle Maguire (Spain), Julian Clare (Korea), Gerry Cunningham (Malawi) and Hilda Ó Riain (Slovakia).
Announcing the nominations, Minister for Foreign Affairs Charlie Flanagan said the new heads of mission would play important roles in the Brexit talks, the drive to expand into EU markets, developing the relationship with the US and strengthening trade in the Gulf and the Asia-Pacific region.