| 01147W | I. RE. LO. Ltd | YES | NO | | N/A | N/A | N/A | Reg-Pending | NO | NO |
| 00374W | I.B.M. International Holdings B.V. | YES | NO | | YES | YES | YES | YES | YES | YES |
| 00373WB | I.B.M. Ireland Ltd | YES | YES | | YES | YES | YES | YES | YES | Reg-Pending |
| 00963W | I.C. Realtime Ltd | YES | NO | | N/A | N/A | YES | YES | YES | YES |
| 01245B | I.M. Automotive Ltd | NO | YES | Subaru Ireland | N/A | N/A | N/A | YES | YES | YES |
| 01388WB | IBB International Bullion & Metal Brokers Ltd | YES | YES | | N/A | N/A | N/A | YES | YES | YES |
| 00103WB | Ibotz (Ireland) Ltd | YES | YES | iBOTZ | YES | YES | YES | YES | YES | YES |
| 00982W | ICI Dulux Paints Ireland | YES | NO | | N/A | N/A | YES | YES | YES | YES |
| 01420WB | IKEA Ireland Ltd | YES | YES | | N/A | N/A | N/A | N/A | YES | YES |
| 00196W | iLight Ltd | YES | NO | | YES | YES | YES | YES | YES | Reg-Pending |
| 01625WB | Ille Paper Service (IRL) Ltd | YES | YES | | Reg-Pending | Reg-Pending | Reg-Pending | Reg-Pending | Reg-Pending | Reg-Pending |
| 00176W | Imex Instruments Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 01521WB | In Hand Guides Ltd | YES | YES | | NO | NO | NO | NO | Reg-Pending | Reg-Pending |
| 01315WB | Indesit Ireland Ltd | YES | YES | | N/A | N/A | N/A | N/A | YES | YES |
| 00696WB | Indur (Wholesale) Ltd | YES | YES | | YES | YES | YES | YES | YES | YES |
| 01048W | Industrial Hygiene & Catering Equipment Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 00505W | INEST Ltd | YES | NO | Digi Net Business Solutions | YES | YES | YES | YES | YES | YES |
| 01074WB | Ingenico Ireland Ltd | YES | YES | | N/A | Reg-Pending | Reg-Pending | Reg-Pending | Reg-Pending | Reg-Pending |
| 01611WB | Ingersoll Rand International Ltd | YES | YES | | N/A | N/A | N/A | YES | YES | YES |
| 01353WB | Instrument Technology Ltd | YES | YES | | Reg-Pending | Reg-Pending | Reg-Pending | Reg-Pending | Reg-Pending | Reg-Pending |
| 00815WB | Integral Computers Ltd | YES | NO | | YES | YES | YES | BATT Reg-Pending | Reg-Pending | Reg-Pending |
| 00186 | INTEK Ltd | YES | NO | | YES | YES | YES | NO | NO | NO |
| 00893 | Intel Ireland Ltd | YES | NO | | YES | YES | Reg-Pending | NO | NO | NO |
| 00773W | International Cash Drawer Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 01574WB | Intertime Ltd | YES | YES | | NO | NO | NO | NO | NO | Reg-Pending |
| 00650WB | Intraveno Healthcare Ltd | YES | YES | | YES | YES | YES | YES | YES | YES |
| 00739WB | IOResource Ltd | YES | YES | | YES | YES | YES | YES | YES | YES |
| 00139W | IQON Technologies Ltd | YES | NO | Iqon Technology | YES | YES | NO | NO | NO | NO |
| 01495WB | Irish Aviation Authority | YES | YES | | Reg-Pending | Reg-Pending | Reg-Pending | NO | Reg-Pending | Reg-Pending |
| 01006W | Irish Broadband Internet Services Ltd | YES | NO | Irish Broadband | YES | YES | YES | YES | YES | YES |
| 00277W | Irish Business Systems Ltd | YES | NO | IBS | YES | YES | YES | YES | YES | YES |
| 00834WB | Irish Cattle Breeding Federation Society Ltd | YES | YES | | YES | YES | YES | YES | YES | Reg-Pending |
| 01205B | Irish Commercials (Sales) Ltd | NO | YES | | N/A | N/A | N/A | YES | YES | Reg-Pending |
| 00644W | Irish Hospital Supplies Ltd | YES | NO | Irish Hospital Supplies | YES | YES | YES | YES | YES | YES |
| 01223B | Irish International Trading Corporation (Cork) PLC | NO | YES | | N/A | N/A | N/A | YES | YES | YES |
| 01024W | Irish Merchants Ltd | YES | NO | | YES | YES | YES | YES | NO | NO |
| 00260W | Irish Power Products Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 01039WB | Irish Response Ltd | YES | YES | Life's 2 Good | N/A | YES | YES | YES | YES | NO |
| 00064WB | Irish Soft Drinks Ltd | YES | YES | Solus Bulbs & Batteries | YES | YES | YES | YES | YES | YES |
| 01299WB | IrishLCD Consulting Ltd | YES | YES | IrishLCD.ie | N/A | N/A | N/A | YES | YES | NO |
| 00792W | Iskus Health Ltd | YES | NO | | YES | YES | YES | YES | YES | YES |
| 01069W | IT Force Limited | YES | NO | | N/A | N/A | YES | YES | YES | YES |
| 01104W | ITW Ireland | YES | NO | | N/A | N/A | YES | YES | YES | YES |