| Flag | Code | Country | Time Difference (GMT) | Group | Comment | Internet Code |
 | 225 | COTE D'IVOIRE (Republic of) | 0 | | Also known as Ivory Coast | ci |
 | 34 | Ibiza | 1 | SPAIN | | es |
 | 354 | ICELAND | 0 | NATO | | is |
 | 91 | INDIA (Republic of) | 4.5 | BCW | | in |
 | 873 | INDIAN OCEAN | | INMARSAT | | |
 | 62 | INDONESIA (Republic of) | 7 | | | id |
| 870 | INMARSAT SNAC | | INMARSAT, GLOBAL | | |
| 882 | International Networks | | GLOBAL | | |
| 991 | International Trial | | GLOBAL | Trial of international telecommunications public correspondence service | |
| x | Internet Code | | | Bouvet Island | bv |
| x | Internet Code | | | Commercial | com |
| x | Internet Code | | | Czechoslovakia | cs |
| x | Internet Code | | | educational | edu |
| x | Internet Code | | | Western Sahara | eh |
| x | Internet Code | | | France Metropolitan | fx |
| x | Internet Code | 0 | UK | United Kingdom - code not in common use | gb |
| x | Internet Code | | | government | gov |
| x | Internet Code | | BRD | South Georgia and South Sandwich Islands | gs |
| x | Internet Code | | | international | int |
| x | Internet Code | | BRD | British Indian Ocean Territory | io |
| x | Internet Code | | | Military | mil |
| x | Internet Code | | | | net |
| x | Internet Code | | | Neutral Zone | nt |
| x | Internet Code | | | non-profit (usually) organisation | org |
| x | Internet Code | | | Svalbard and Jan Mayen Islands | sj |
| x | Internet Code | | | USSR (former) | su |
| x | Internet Code | | | French Southern Territories | tf |
| x | Internet Code | | USA | United States Minor Outlying Islands | um |
| 979 | IPRS | | GLOBAL | International Premium Rate Service - Reserved Code | |
 | 98 | IRAN (Islamic Republic of) | 3.5 | | | ir |
 | 964 | IRAQ (Republic of) | 3 | | | iq |
 | 353 | IRELAND (REPUBLIC OF) | 0 | EU | Eire | ei |
| 808 | ISCS | | GLOBAL | International Shared Cost Service - Reserved Code | |
 | 44 | Isle of Man | 0 | UKD | Manx | im |
 | 970 | Israel (Palestine) | 2 | | | |
 | 972 | ISRAEL (State of) | 2 | | | il |
 | 39 | ITALY | 1 | EU, NATO, ITALY | | it |