If you are doing it through a work arrangement, your employer will deduct the pension through your payroll. It is known as a net pay arrangement.
If you are doing it yourself, you have two options:
Send the PRSA Cert to the Revenue and have them adjust your tax credits. You pay the gross amount from your bank account but your net salary will be higher, so it has the same effect as the net pay arrangement.
Claim back all the premiums paid in 2017 by submitting a tax return in 2018.
Steven
http://www.bluewaterfp.ie (www.bluewaterfp.ie)