| Island's name | Island group(s) | Country/Countries |
|---|
| Ibicuy | Paraná Delta |  Argentina |
| Ibiza |  Balearic Islands |  Spain |
| Iceland | |  Iceland |
| Ida | Torres Strait Islands,  Queensland |  Australia |
| Idanha | Beira Baixa islands |  Portugal |
| Idjwi | Lake Kivu |  Democratic Republic of the Congo |
| Iejima | Okinawa Islands part of the Ryukyu Islands |  Japan |
| Iheyajima | Okinawa Islands part of the Ryukyu Islands | Japan |
| IJsselmonde |  South Holland |  Netherlands |
| Ikaria | |  Greece |
| Ikema | Miyako Islands part of the Sakishima Islands part of the Ryukyu Islands | Japan |
| Île Aganton | English Channel |  France |
| Île d'Ouessant | English Channel | France |
| Île d'Yeu |  Pays de la Loire | France |
| Île-d'Aix | | France |
| Île-d'Arz | Gulf of Morbihan | France |
| Île des Sœurs | Bassin de Laprairie |  Canada |
| Île-Grande | English Channel | France |
| Île Milliau | English Channel | France |
| Île Sainte-Marguerite | Lérins Islands | France |
| Îles-de-Boucherville | St. Lawrence River | Canada |
| Îlot Saint-Ferréol | Lérins Islands | France |
| Île Saint-Honorat | Lérins Islands | France |
| Îles Sainte-Thérèse | St. Lawrence River | Canada |
| Îlot de la Tradelière | Lérins Islands | France |
| Îles d'Hyères | Île du Levant, Île de Porquerolles, and Île de Port-Cros | |
| Ilha Grande | |  Brazil |
| Ilhas Cagarras | Guanabara Bay | Brazil |
| Ilovik | Adriatic Sea |  Croatia |
| Inaccessible |  Tristan da Cunha |  British overseas territory of Saint Helena, Ascension and Tristan da Cunha |
| Inaccessible | South Orkney Islands | Claimed by:
United Kingdom as part of the  Falkland Islands and by
Argentina |
| Inaccessible | Dellbridge Islands | Antarctica |
| Inexpressible | | Claimed by:  New Zealand,  Antarctica |
| Indian | Rock River,  Illinois |  United States |
| Indian | Lake Huron,  Ontario | Canada |
| Ingarö | |  Sweden |
| Ingram | Queensland | Australia |
| Inhaca | |  Mozambique |
| Inish Beg | Lough Erne | United Kingdom |
| Inish Conra | |  Ireland |
| Inish Davar | | Ireland |
| Inish Divann | | Ireland |
| Inish Doney | Lough Erne | Ireland |
| Inish Fovar | Lough Erne | Ireland |
| Inish Free | Lough Gill | Ireland |
| Inish Lougher | Lough Erne | Ireland |
| Inish More | Lough Erne | Ireland |
| Inishbiggle | County Mayo | Ireland |
| Inishbofin | County Donegal | Ireland |
| Inishbofin | County Galway | Ireland |
| Inishcorkish | Upper Lough Erne | Ireland |
| Inisheer | Aran Islands | Ireland |
| Inishkea North | County Galway | Ireland |
| Inishkea South | County Galway | Ireland |
| Inishleague | Lough Erne | Ireland |
| Inishlirroo | Upper Lough Erne | Ireland |
| Inishlught | Upper Lough Erne | Ireland |
| Inishmaan | Aran Islands | Ireland |
| Inishmacsaint | Lough Erne | Ireland |
| Inishmakill | Lough Erne | Ireland |
| Inishmore | Aran Islands | Ireland |
| Inishmurray | | Ireland |
| Inishark | | Ireland |
| Inishturk | Lough Erne | Ireland |
| Innarahu | Baltic Sea |  Estonia |
| Innetalling | Hudson Bay,  Nunavut | Canada |
| Innisfallen | Lough Leane | Ireland |
| Insua | Minho islands | Portugal |
| Iona | Inner Hebrides |  Scotland |
| Iona | Strait of Georgia | Canada |
| Iona | Placentia Bay | Canada |
| Iona | Hudson River | United States |
| Ios | Cyclades | Greece |
| Iowa | Mississippi River, Illinois | United States |
| Irabu | Miyako Islands part of the Sakishima Islands part of the Ryukyu Islands | Japan |
| Irakleia | Cyclades | Greece |
| Ireland (island) | | Ireland, United Kingdom |
| Ireland's Eye | County Dublin | Ireland |
| Iriomote | Yaeyama Islands part of the Sakishima Islands part of the Ryukyu Islands | Japan |
| Ischia | Gulf of Naples |  Italy |
| Ishigaki | Yaeyama Islands part of the Sakishima Islands part of the Ryukyu Islands | Japan |
| Island 526 | Mississippi River,  Missouri | United States |
| Island No. 8 | Mississippi River,  Kentucky | United States |
| Island No. 21 | Mississippi River,  Tennessee | United States |
| Island No. 30 | Mississippi River, Tennessee and  Arkansas | United States |
| Island No. 63 | Mississippi River,  Mississippi | United States |
| Island No. 317 | Mississippi River, Illinois | United States |
| Island of Montreal |  Quebec | Canada |
| Islands of St. Paul | Maltese islands |  Malta |
| Islas Cíes | belonging to the Spanish province of Pontevedra, in Galicia | Spain |
| Islay | Inner Hebrides | Scotland |
| Isle of Man | Irish Sea | Crown dependency |
| Isle of Rest | Georgian Bay | Canada |
| Isle of Thanet | British Isles | United Kingdom |
| Isle of Wight | In Roman times was referred to as Vectis | United Kingdom |
| Isle of Youth | Greater Antilles |  Cuba |
| Isola di San Michele | Venetian Lagoon | Italy |
| Isola Maggiore | Lake Trasimeno | Italy |
| Isra-Tu | Dahlak Archipelago |  Eritrea |
| Ist | | Croatia |
| Itamaracá | | Brazil |
| Ithaca | Ionian Islands | Greece |
| Itu Aba | Spratly Islands | Administered by
 Republic of China,
Claimed by:
 China,
 Vietnam, and
 Philippines |
| Isla Ixtapa | Ixtapa/Zihuatanejo,  Guerrero |  Mexico |
| Iž | | Croatia |
| Izenajima | Okinawa Islands part of the Ryukyu Islands | Japan |
