| Rank | Name | IPv4 addresses | IPv6 /64 networks | AS numbers | Prefixes |
|---|---|---|---|---|---|
| Ljosleidarinn ehf | 353,024 | 233 | 2 | 35 | |
| Mila hf | 140,800 | 235 | 1 | 13 | |
| Rannsokna- og haskolanet Islands hf. | 131,072 | 232 | 1 | 3 | |
| 4 | Advania Island ehf | 72,448 | 1.5 x 225 | 3 | 43 |
| 5 | Nova hf | 47,104 | 1.25 x 235 | 1 | 20 |
| 6 | Opin Kerfi hf | 21,504 | 1.13 x 235 | 4 | 18 |
| 7 | Hringdu ehf | 19,968 | 235 | 1 | 9 |
| 8 | deCode Inc. | 12,288 | 0 | 1 | 3 |
| 9 | Reykjavik City Hall | 10,240 | 0 | 1 | 3 |
| 10 | Origo hf | 9,472 | 232 | 1 | 5 |
| 11 | Eignafelag Tolvunar ehf | 8,704 | 0 | 1 | 3 |
| 12 | Hringidan ehf / Vortex Inc | 8,192 | 235 | 1 | 2 |
| 13 | Landsbankinn hf | 8,192 | 0 | 1 | 1 |
| 14 | Icelandic Ministry of Education | 8,192 | 0 | 1 | 1 |
| 15 | FlokiNET ehf | 5,632 | 1.5 x 218 | 1 | 26 |
| 16 | Sensa ehf | 5,120 | 1.13 x 235 | 2 | 7 |
| 17 | 1984 ehf | 4,608 | 232 | 1 | 5 |
| 18 | Farice ehf | 4,352 | 232 | 2 | 8 |
| 19 | Snerpa ehf | 4,352 | 0 | 1 | 2 |
| 20 | Wintermute Technologies EHF | 4,096 | 0 | 1 | 13 |