List of the top 20 organizations with the largest IP allocations in Spain
| Rank | Name | IPv4 addresses | IPv6 /64 networks | AS numbers | Prefixes |
|---|---|---|---|---|---|
| TELEFONICA DE ESPANA S.A.U. | 10,779,392 | 1.02 x 241 | 3 | 362 | |
| VODAFONE ONO, S.A. | 2,851,072 | 238 | 2 | 94 | |
| Entidad Publica Empresarial Red.es | 1,539,584 | 232 | 1 | 39 | |
| 4 | R Cable y Telecable Telecomunicaciones, S.A.U. | 400,640 | 225 | 1 | 33 |
| 5 | Santander Global Technology, S.L.U | 148,224 | 0 | 1 | 134 |
| 6 | Fundacion Tecnalia Research and Innovation | 131,072 | 0 | 1 | 45 |
| 7 | SAREnet, S.A. | 75,008 | 232 | 1 | 9 |
| 8 | Tele Elda SA | 20,224 | 235 | 1 | 28 |
| 9 | Fujitsu Technology Solutions, S.A. | 19,968 | 0 | 1 | 7 |
| 10 | Wiva Telecom S.L. | 19,968 | 0 | 1 | 56 |
| 11 | Comvive Servidores S.L. | 15,872 | 232 | 1 | 65 |
| 12 | FIBERGREEN TECNOLOGICAS S.L. | 15,360 | 0 | 1 | 30 |
| 13 | Networksland SL | 14,336 | 0 | 1 | 49 |
| 14 | Esystel Servicios Multimedia, SL | 8,448 | 0 | 1 | 2 |
| 15 | Cablemel S.L. | 8,192 | 0 | 1 | 2 |
| 16 | Alhambra Systems SA | 8,192 | 232 | 1 | 20 |
| 17 | Ibivision S.A.U. | 8,192 | 0 | 1 | 1 |
| 18 | AVATEL TELECOM, SA | 7,936 | 0 | 5 | 16 |
| 19 | WIFINITY GLOBAL NETWORK, S.L. | 7,424 | 0 | 1 | 29 |
| 20 | Xarxes de Telecomunicacions Alternatives SL | 7,424 | 1.13 x 235 | 1 | 10 |