| Rank | Name | IPv4 addresses | IPv6 /64 networks | AS numbers | Prefixes |
|---|---|---|---|---|---|
| HEAnet CLG | 1,843,200 | 232 | 1 | 18 | |
| Vodafone Ireland Limited | 1,274,368 | 0 | 2 | 245 | |
| Eircom Limited | 1,111,296 | 235 | 1 | 30 | |
| 4 | Amazon Data Services Ireland Ltd | 935,936 | 1.62 x 230 | 1 | 151 |
| 5 | Imagine Communications Group Limited | 495,872 | 232 | 1 | 70 |
| 6 | BT Communications Ireland Limited | 438,016 | 1.13 x 235 | 2 | 16 |
| 7 | Digiweb ltd | 248,096 | 1.63 x 235 | 2 | 66 |
| 8 | Three Ireland (Hutchison) limited | 241,408 | 0 | 1 | 69 |
| 9 | Coolwave Communications Limited | 156,160 | 0 | 1 | 5 |
| 10 | Magnet Networks Limited | 123,392 | 1.25 x 235 | 2 | 26 |
| 11 | University College Dublin | 65,536 | 0 | 1 | 1 |
| 12 | Fulnett Limited | 42,240 | 232 | 1 | 9 |
| 13 | Blacknight Internet Solutions Limited | 34,816 | 236 | 3 | 45 |
| 14 | ServeCentric Ltd. | 32,768 | 0 | 1 | 1 |
| 15 | Irish Government | 26,624 | 232 | 2 | 25 |
| 16 | Meteor Mobile Communications Limited | 24,832 | 232 | 1 | 8 |
| 17 | Google Ireland Limited | 21,760 | 224 | 1 | 7 |
| 18 | Afilias Ltd | 20,992 | 1.28 x 222 | 2 | 164 |
| 19 | Jurgita Jurgaitienei trading as LOCOTORPI | 20,480 | 0 | 1 | 58 |
| 20 | CORK INTERNET EXCHANGE LIMITED | 19,968 | 233 | 1 | 17 |