Revenue eBrief No. 170/25

05 September 2025

Guidance on Pillar Two - Registration

Tax and Duty Manual Part 04A-01-01A is a new manual created to provide detailed guidance regarding the registration process for Pillar Two taxes.

Entities within scope of Pillar Two taxes (the IIR top-up tax, UTPR top-up tax, or Domestic Top-up Tax) must register for the relevant taxes with Revenue no later than 12 months after the last day of the first fiscal year in which they become subject to the relevant tax.

The deadline for in-scope entities to register with Revenue is 31 December 2025. To allow ample time for agents and business to get familiar with the new process, the registration portal has been released and is now live on ROS. 

The registration portal also requires entities to register for the Top-up Tax Information Return (TIR) to allow them notify Revenue whether the TIR will be filed in Ireland or by a Designated Filing Entity in another jurisdiction.

As part of our engagement strategy Revenue has created a Pillar Two Hub on our website. This will be used to provide key information and updates on Pillar Two. With regard to the registration process we are writing to taxpayers in phases. The first phase of letters issued to Irish Ultimate Parent Entities (UPEs) in mid-August 2025. The second phase of letters will issue shortly to the constituent entities of the Irish UPEs.