| Abbreviation | Definition |
|---|---|
| IS | Island |
| ISAL | International Surface Air Lift |
| ISBN | International Standard Book Number |
| ISC | Information Service Center |
| ISSC | Information Systems Service Center |
| ISSN | International Standard Serial Number |
| ISSP | Incoming Secondary Sorting Program |
| ITK | Infrastructure Tool Kit |
| IXL | Illiterate Xponents Lack |
| JARAP | Joint Alternate Route Adjustment Process |
| JM | Jamaica |
| JO | Jordan |
| JP | Japan |
| KE | Kenya |
| KG | Kyrgyzstan (Kyrgyz Republic) |
| KH | Cambodia |
| KI | Kiribati |
| KM | Comoros |
| KN | Saint Kitts and Nevis |
| KP | Korea (North) (People's Republic) |