Regardless of whether you're Prepay or Bill Pay with O2, O2 say that you have to fill out an online request form for them to give you the unlock code.
You'll find this at http://www.o2.ie/help/unlock-request.php
Once you've submitted the request the code will be sent to you via text or email in a couple of days.
If you’re waiting a few days you can get them on Facebook, Twitter and on their online forum to speed things up.
Pre Pay
If you're on prepay then your phone must be registered on o2.ie and have topped up €150 since you registered it (you probably registered it when you got it to allow you to top-up online).
If you've topped up by less than €150, O2 may ask you to pay the remaining balance before they'll give you the code.
Bill Pay
If you're on bill pay then you'll need to request your unlock code before O2 will tell you the criteria needed.
You can also try calling their care line on 1747 (14c per call) if you're on pre pay or 1909 (free call) if you're on bill pay.
