| International University Study Center | |
| International Venture Consultants | Madrid |
| Internet Galicia | Lugo |
| Internet Kioskos | Madrid |
| Internet Republica, S.L. | Madrid |
| Internet Security Auditors, S.L. | Barcelona |
| Internet Web Serveis | Lleida |
| Internet Web Solutions | Málaga |
| Internext Interactive Creativity, S.L. | Barcelona |
| Internxt Universal Technologies, S.L. | Valencia |
| Intervia | Madrid |
| Intexmedia, S.L. | Cáceres |
| INTIA | |
| Intraempresas | Madrid |
| INTRAS | |
| Intuate | Barcelona |
| INTUIX | Barcelona |
| InvBit, diseño y desarrollo web, S.L. | A Coruña |
| Invelco, S.A. | Madrid |
| Invelon Technologies, S.L. | Lleida |
| Inventivo | Balearic Islands |
| Inventum Marketing | |
| Inveready | Barcelona |
| Invest in Spain | Madrid |
| Investigación y Programas, S.A. | Madrid |
| Invivo Capital | Barcelona |
| Invivo Partners | |
| Inxenio | A Coruña |
| ioBuilders | Madrid |
| IOMarketing | |
| IOMED | Barcelona |
| Ione Team | Madrid |
| IoT Stars | Barcelona |
| IP Marketing | |
| iPadizate | |
| Iphonedroid | |
| IPligence | Barcelona |
| IPM Electrónica, S.L. | Madrid |
| IPMark | Madrid |
| Ipo Networks | Alicante |
| iPractic | Barcelona |
| iPronics | Valencia |
| IPv6 Informatique, S.L. | Murcia |
| IQS Barcelona | |
| IQS Tech Factory | Barcelona |
| Iquadrat | Barcelona |
| IRB Barcelona | |
| IRC Computer | Málaga |
| Iris611 | Barcelona |
| Irisbond Crowdbonding, S.L. | |