| 1 | ISL | Eagle Air Ltd. (Arnarflug H/F) | Callsign: Eagleair, Designator VL recalled by IATA | IS | AVCODES |
| 2 | ISL | Eagle Air Ltd. (Arnarflug H/F) | IATA: VL, Callsign: Eagleair, Designator VL recalled by IATA | IS | AVCODES |
| 3 | ISL | Landsflug ehf | IATA: X9, Name changed to City Star Airlines ehf | IS | AVCODES |
| 4 | ISL | City Star Airlines ehf | IATA: X9, Callsign: Islandia, Ceased operation on 30 January 2008. Designator X9 re-instated by IATA. Name changed from Landsflug ehf | IS | AVCODES |
| 5 | ISL | Flugfélag Austurlands | Callsign: Eastland, | IS | AVCODES |
| 6 | ISL | Landsflug | | | ICAO1 |
| 7 | ISL | Island Line Ltd. | Real: IL, 1999: 13.4km standard gauge, electrified at 660V= 3rd rail | GB | TRAFFIC |
| 8 | ISL | Infraserv Logistics GmbH | | DE | VKM |
| 9 | ISLA | ISLAND AIR SERVICE | | | SCAC4 |
| 10 | ISLC | ISLAND CARGO CONSOLIDATORS, INC. | | | SCAC1 |
| 11 | ISLC | ISOLAB INC | | | SCAC4 |
| 12 | ISLD | ISLAND TOWING LTD | | | SCAC4 |
| 13 | ISLE | ISLE LOADEM | | | SCAC4 |
| 14 | ISLJ | INTEGRAL SOLUTIONS LLC | | | SCAC4 |
| 15 | ISLL | ISLAND TRANSPORT LTD | | | SCAC4 |
| 16 | ISLS | ISLAND SHIPPING LTD | | | SCAC4 |
| 17 | ISLT | ISLAND TUG & BARGE CO | | | SCAC4 |
| 18 | ISLU | INDUSTRIAL SOLVENTS & CHEMICALS PVT, LTD | | IND | BIC |
| 19 | ISLU | *ISLANDIA LIMITED | | | PWRC |
| 20 | ISLU | *RETIRED 04-06-93 ATP | | | PWRC |
| 21 | ISLU | Islandia | | | RSRV |
| 22 | ISLU | INDUSTRIAL SOLVENTS & CHEMICALS PVT | | | SCAC4 |
| 23 | ISLV | ISLAND ENVIRONMENTAL SERVICES INC | | | SCAC4 |
| 24 | ISLY | INTERSPEC SYSTEMS LIMITED | | | SCAC4 |
