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Contact Us 

The SEMO Helpdesk provides an information service for all interested parties.

SEMO Helpdesk availability:  Mon-Fri from 9:00am - 5.00pm.



The SEMO Helpdesk is available Mon-Fri from 9.00am until 5.00pm. We operate a voicemail service if we are unavailable.

ROI: 1800 726 772

NI: 0800 072 6772

International: +353 1 237 0584



If you are required to fax information to us, our fax numbers are:

  • ROI: +353 1 526 6416


If you are required to post information to us please use the relevant address below:

  • SEMO Customer Service                   
  • 160 Shelbourne Road                        
  • Ballsbridge
  • Dublin 4
  • D04 FW28
  • Republic of Ireland
  • SEMO Customer Service
  • Castlereagh House
  • 12 Manse Road
  • Belfast BT6 9RT
  • Northern Ireland

If you are visiting us please see below links to a interactive Google maps displaying both our locations:

Castlereagh House, Belfast Interactive Map

The Oval, Dublin 4 Interactive Map

Complaints Procedure

If you are unhappy with the quality of service you have received, you have the right to complain. Please direct these complaints to and your complaint will be addressed.

As per the Trading & Settlement Code participants may raise a dispute in respect of a Data or Settlement query. For further information please see and review Agreed Procedure 14 – Disputes.

Please view SEMO's full Customer Charter here.


SEMO is a joint venture between EirGrid PLC and SONI Limited