The Taoiseach will meet the British Prime Minister in Dublin later today.
Before that, Theresa May travels to Cardiff, where she will meet representatives of the devolved governments in Northern Ireland, Scotland and Wales. Among those attending that meeting will be Stormont's outgoing First Minister Arlene Foster and Sinn Fein's Northern Ireland leader Michelle O'Neill.
This will be Theresa May's first visit to Dublin since she became British Prime Minister and follows on from Enda Kenny's meeting with Theresa May in Downing Street last year.
They've spoken in recent weeks on the phone to discuss the crisis in Northern Ireland and that issue will be up for discussion today.
It's the first meeting between the two since Mrs May outlined her intentions to opt for a hard Brexit.
And so the main focus of their talks will be how they can maintain the common travel area and no return to a hard border between North and South with the UK outside the single market, customs union and curbing immigration.