| Organization | Blocks | Addresses | First registered |
|---|---|---|---|
| Valeo Vision Systems | 3 | 50.3 million | 28 Jul 2011 |
| Intune Networks | 2 | 16.8 million | 30 Jul 2008 |
| Airvod Limited | 1 | 16.8 million | 7 Mar 2007 |
| Alps Electric (Ireland) Ltd | 1 | 16.8 million | 1 Sep 2020 |
| Analog Devices, Inc | 1 | 16.8 million | 23 Sep 2018 |
| ASITA TECHNOLOGIES INT'L LTD. | 1 | 16.8 million | 8 Sep 2000 |
| BUSTEC PRODUCTION LTD. | 1 | 16.8 million | 8 Sep 2000 |
| CG Power Systems Ireland Limited | 1 | 16.8 million | 29 Sep 2004 |
| Cloudium Systems Ltd. | 1 | 16.8 million | 30 Dec 2012 |
| Controlled Electronic Manageme | 1 | 16.8 million | 8 Sep 2000 |
| Curtiss-Wright Controls Avionics & Electronics | 1 | 16.8 million | 21 Jan 2003 |
| Cylon Controls | 1 | 16.8 million | 3 Apr 2004 |
| DIGITAL ENGINEERING LTD. | 1 | 16.8 million | 8 Sep 2000 |
| Druid Software | 1 | 16.8 million | 1 Oct 2023 |
| Easy Digital Ltd. | 1 | 16.8 million | 3 Feb 2012 |
| Ei Electronics | 1 | 16.8 million | 23 Mar 2026 |
| Eurologic Systems, Ltd. | 1 | 16.8 million | 8 Sep 2000 |
| Europlex Technologies | 1 | 16.8 million | 17 Mar 2004 |
| Fijowave Limited | 1 | 16.8 million | 23 Aug 2013 |
| Galvanic Ltd | 1 | 16.8 million | 18 Jun 2008 |
| Homenet Communications | 1 | 16.8 million | 29 Mar 2002 |
| Ircona | 1 | 16.8 million | 29 Nov 2006 |
| Ivron Systems | 1 | 16.8 million | 8 Sep 2000 |
| Klas Ltd | 1 | 16.8 million | 6 Mar 2005 |
| Lake Communications | 1 | 16.8 million | 8 Sep 2000 |
| MDS Gateways | 1 | 16.8 million | 30 Jan 2002 |
| MI-Zone Technology Ireland | 1 | 16.8 million | 24 Sep 2011 |
| RAIDTEC LTD. | 1 | 16.8 million | 22 Apr 1998 |
| Silicon & Software Systems Ltd. | 1 | 16.8 million | 2 Dec 2010 |
| SPECTEL LTD. | 1 | 16.8 million | 8 Sep 2000 |
| TE Connectivity Limerick | 1 | 16.8 million | 27 Apr 2010 |
| Telecom Technology Ltd. | 1 | 16.8 million | 24 Oct 2001 |
| The Now Factory | 1 | 16.8 million | 17 Nov 2012 |
| Xunison Ltd. | 1 | 16.8 million | 6 Jun 2020 |
| ACT | 4 | 1.1 million | 30 Jul 2008 |
| HKC Security Ltd. | 4 | 1.1 million | 9 Mar 2014 |
| ProPhotonix | 2 | 1.1 million | 31 May 2009 |
| Tekelek Europe Ltd | 2 | 1.1 million | 25 Nov 2012 |
| Blacknight Internet Solutions Limited | 1 | 1 million | 17 Apr 2020 |
| EchoStar Mobile | 1 | 1 million | 23 Apr 2022 |
| Ersúles Limited | 1 | 1 million | 17 Jul 2016 |
| Fortis Medical Devices LTD | 1 | 1 million | 1 May 2026 |
| Gigawave | 1 | 1 million | 10 Oct 2020 |
| Joule Group Limites | 1 | 1 million | 4 Nov 2023 |
| Neuromod Devices Ltd. | 1 | 1 million | 21 Jun 2026 |
| Thermalimage | 1 | 1 million | 22 Jul 2021 |
| Baker Hughes EMEA | 2 | 8.2 thousand | 22 Jan 2022 |
| Benetel | 2 | 8.2 thousand | 15 Jan 2019 |
| Ash Technologies | 1 | 4.1 thousand | 12 Mar 2017 |
| Ashling Microsystems Ltd. | 1 | 4.1 thousand | 30 Jul 2008 |
| Connor Winfield LTD | 1 | 4.1 thousand | 27 Jul 2014 |
| Diagnosys Test Systems Ltd | 1 | 4.1 thousand | 6 Oct 2013 |
| Embedded Labs | 1 | 4.1 thousand | 8 May 2011 |
| Fortus | 1 | 4.1 thousand | 13 Aug 2025 |
| Global Security Devices | 1 | 4.1 thousand | 10 Jan 2010 |
| Grenmore Ltd | 1 | 4.1 thousand | 13 Sep 2009 |
| GridBeyond | 1 | 4.1 thousand | 11 Mar 2023 |
| ICP NewTech Ltd | 1 | 4.1 thousand | 23 Mar 2014 |
| Infineer Ltd. | 1 | 4.1 thousand | 30 Jul 2008 |
| Integra LifeSciences (Ireland) Ltd | 1 | 4.1 thousand | 30 Aug 2009 |
| Linxpeed Limited | 1 | 4.1 thousand | 12 Dec 2023 |
| SAMH Engineering Services | 1 | 4.1 thousand | 4 Jan 2009 |
| Trinity College Dublin | 1 | 4.1 thousand | 16 Oct 2016 |
| TxWireless Limited | 1 | 4.1 thousand | 20 Oct 2023 |
| Ubotica Technologies | 1 | 4.1 thousand | 3 Jun 2023 |
Every organization with blocks registered in Ireland, sorted by total address space.