In general, you are subject to the Social Security legislation of the country where you work. Therefore, if you come to work in Ireland you will normally be subject to Irish social security law and pay social insurance (PRSI) contributions here.
Similarly, if you go to work in the U.S.A., you will be subject to the U.S.A. social security laws and may have to pay social security contributions there.
If you are sent by an Irish employer to work in the U.S.A. on a temporary assignment, you will continue to pay Irish PRSI contributions up to the first five (5) years of your employment in the U.S.A..
Therefore, if you are at present working in Ireland and are being sent to work in the U.S.A. on a temporary assignment, you or your employer should contact the following section:
PRSI Special Collections
Department of Social Protection
LoCall 1890 690 690 (from the Republic of Ireland only), or
+353 14 715898 (from Northern Ireland or overseas)
This should be done as early as possible, so that the necessary forms and advice can be given.