Any person is free to travel from the State regardless of whether their Irish Residence Permit (IRP) card is in date or has expired.
Non visa-required nationals trying to re-enter the State may rely on their in-date IRP card or will need to provide proof of their permission to reside in the State, such as a letter from my Department, to an immigration officer on their arrival in the State.
If a person's IRP card has expired and they are a visa-required national, then they will require a visa to return to the State. They can apply to their local Visa Office/Embassy for the relevant visa to allow them to travel back to Ireland.
Entry into the State is solely at the discretion of the Immigration Officer at the port of entry. The onus is on the individual to have all documentation relating to their reasons for entering Ireland ready for presentation to the immigration officer to gain entry.
Further information is available on my Department's immigration website at: www.irishimmigration.ie.