| Islay Spirits Limited | Private company limited by shares | Live |
| ISL.CRESCERE CO LIMITED | Private company limited by shares | Live |
| DRAGON ISLE LIMITED | | Live |
| EMERALD ISLE LIMITED | Private company limited by shares | Live |
| HARBOUR ISLE LIMITED | Private company limited by shares | Dissolved |
| MID ISLE PUBLICATIONS LIMITED | Private company limited by shares | Live |
| Isle of South Company Limited | Private company limited by shares | Live |
| ISLECO LIMITED | Private company limited by shares | Live |
| ISLEDON LIMITED | Private company limited by shares | Dissolved |
| ISLEHAM ENTERPRISES LIMITED | Private company limited by shares | Live |
| ISLER LIMITED | Private company limited by shares | Dissolved |
| Isler & Company Limited | | Live |
| Emerald Isles Company Limited | Private company limited by shares | Live |
| ISLETON LIMITED | Private company limited by shares | Dissolved |
| Islet-Studio Limited | | Live |
| ISLI & MPR International Foundation Limited | Private company limited by shares | Live |
| ISLINGFORD LIMITED | Private company limited by shares | Live |
| ISLINGSON COMPANY LIMITED | Private company limited by shares | Dissolved |
| ISLINGTON LIMITED | Private company limited by shares | Dissolved |
| ISLINGTON ASIA LIMITED | Private company limited by shares | Live |
| ISLINGTON ASIA PACIFIC LIMITED | Private company limited by shares | Dissolved |
| ISLION CHINA LIMITED | Private company limited by shares | Dissolved |
| ISLNET SOLUTIONS LIMITED | Private company limited by shares | Dissolved |
| ISLORN COMPANY LIMITED | Private company limited by shares | Live |
| Islov Pets Company Limited | | Live |
| ISLT LIMITED | Private company limited by shares | Live |