| Island's name | Island group(s) | Country/Countries |
| Saaremaa | West Estonian Archipelago; Baltic Sea | Estonia |
| Saarnaki laid | Väinameri Sea | Estonia |
Saba  | Lesser Antilles | Netherlands |
| Cayo Sabinal | Greater Antilles | Cuba |
| Sable | Nova Scotia | Canada |
| Sabrina | Balleny Islands | Ross Dependency, New Zealand |
| Sabula | Iowa | United States |
| Saddle | South Orkney Islands | Claimed by:
United Kingdom as part of the Falkland Islands and by Argentina |
| Safra | Alentejo islands | Portugal |
| St Agnes | Isles of Scilly | United Kingdom |
| Saint Anastasia | Black Sea | Bulgaria |
| Saint Andrews | Admiralty Islands | Papua New Guinea |
| St. Armands Key | | United States |
| Saint Barthélemy | Lesser Antilles | France |
| Saint Catherine | Susquehanna River, Maryland | United States |
| Saint Catherine | Potomac River, Maryland | United States |
| Saint Clement's | Potomac River, Maryland | United States |
| Saint Croix | United States Virgin Islands, Lesser Antilles | United States |
| Saint Croix | Saint Croix River, Maine | United States |
| Saint Cyicus | Black Sea | Bulgaria |
| Saint Eustratius | | Greece |
| Saint George | Potomac River, Maryland | United States |
| Saint Giles | Lesser Antilles | Trinidad and Tobago |
| Saint Ivan | Black Sea | Bulgaria |
Saint Helena  | | British overseas territory of Saint Helena, Ascension and Tristan da Cunha |
| St. Helena Island (Maryland) | Maryland | United States |
| Saint Helena | Straits of Mackinac, Michigan | United States |
| Saint Helena | Sea Islands, South Carolina | United States |
| Saint Helena | Little Round Bay, Maryland | United States |
| Île Saint-Honorat | Lérins Islands | France |
| Saint Helen's | St. Lawrence River, Quebec | Canada |
| Saint John | United States Virgin Islands, Lesser Antilles | United States |
| Saint Johns | Missouri River, Missouri | United States |
| Saint Joseph | Ontario | Canada |
| Saint Kitts | Lesser Antilles | Saint Kitts and Nevis |
| Saint Lawrence | Bering Sea, Alaska | United States |
| Saint Lucia | Lesser Antilles | Saint Lucia |
| Saint Margaret | Potomac River, Maryland | United States |
| Île Sainte-Marguerite | Lérins Islands | France |
| Saint Martin | Lesser Antilles | Divided between: France and
Kingdom of the Netherlands |
| Saint Martin | Otago Harbour | New Zealand |
| Saint Martin's | Isles of Scilly | United Kingdom |
| Saint Martin Island | Bay of Bengal | Bangladesh |
| St Mary's | Isles of Scilly | United Kingdom |
| Saint Matthew | Bering Sea, Alaska | United States |
| St. Maurice Towhead | Mississippi River, Louisiana | United States |
| Saint Paul | Nova Scotia | Canada |
| Saint Paul | Pribilof Islands, Alaska | United States |
| Île Saint-Paul | French Southern Territories, Indian Ocean | France |
| Saint Peter | Black Sea | Bulgaria |
| Saint Pierre | Manokin River, Maryland | United States |
| Saint Simons | Golden Isles of Georgia, Georgia | United States |
| Saint Thomas | United States Virgin Islands, Lesser Antilles | United States |
| Saint Vincent | Lesser Antilles | Saint Vincent and the Grenadines |
| Saint Vincent | Florida | United States |
| Sakhalin | North Pacific, Sakhalin Oblast | Russia |
| Salamina | Saronic Islands | Greece |
| Salawati | Raja Ampat Islands | Indonesia |
| Salina | Aeolian Islands | Italy |
| Salisbury | Nunavut | Canada |
| Salsette | Maharashtra | India |
| Saltholm | Øresund | Denmark/ Sweden |
| Saltspring | Gulf Islands, British Columbia | Canada |
| Samalga | Fox Islands group of the Aleutian Islands, Alaska | United States |
| Samar | Visayas | Philippines |
| Samhah | Socotra | Yemen |
| Samos Island | Beira Litoral Islands | Portugal |
| Samos | Dodecanese | Greece |
| Samothrace | | Greece |
| Samphrey | Shetland Islands | Scotland |
| Sampson | Pleasant Bay, Cape Cod, Massachusetts | United States |
| Samsø | Kattegat | Denmark |
| Samson | Isles of Scilly | United Kingdom |
| San Andrés | San Andrés y Providencia | Colombia |
| San Benedicto | Revillagigedo Islands, Colima | Mexico |
| San Benitos | | Mexico |
| San Clemente Island | Channel Islands of California, California | United States |
| San Cristobal | Solomon Islands | Solomon Islands |
| San José | Baja California Sur | Mexico |
| San Jose | Texas | United States |
| San Juan | San Juan Islands, Washington | United States |
| San Martiño | Galicia | Spain |
| San Miguel | Channel Islands of California, California | United States |
| San Nicolas | Channel Islands of California, California | United States |
| San Pietro | Sardinia | Italy |
| San Salvador | The Bahamas | Bahamas |
| Sanak | Sanak Islands, Gulf of Alaska, Alaska | United States |
| Sand Cay | Spratly Islands | Disputed between: China,
Republic of China,
Vietnam,
Brunei,
Philippines, and
Malaysia |
| Sand | Ohio River, Kentucky | United States |
| Sand | Hawaii | United States |
| Sanday | The North Isles, Orkney Islands | Scotland |
| Sandoy | Faroe Islands | Denmark |
| Sandwip | Bay of Bengal | Bangladesh |
| Sandy | Georgian Bay, Ontario | Canada |
| Sandy | Nanticoke River, Maryland | United States |
| Sandy Point | Newfoundland and Labrador | Canada |
| Sandy Point | Sinepuxent Bay, Maryland | United States |
| Sannak | Fox Islands group of the Aleutian Islands, Alaska | United States |
| Sans Souci | Georgian Bay Ontario | Canada |
| Santa Ana | Solomon Islands | Solomon Islands |
| Santa Barbara | Channel Islands of California, California | United States |
| Santa Catalina | Channel Islands of California, California | United States |
| Santa Clara | Juan Fernández archipelago, Chile | Chile |
| Santa Cruz | Channel Islands of California, California | United States |
| Santa Isabel | Solomon Islands | Solomon Islands |
| Santa Margarita | Baja California Sur | Mexico |
| Santa Maria | Azores | Portugal |
| Santa Rosa | Channel Islands of California, California | United States |
| Santa Rosa | Florida | United States |
| Santorini | Cyclades | Greece |
| São Brás | Alentejo islands | Portugal |
| São Jorge | Azores | Portugal |
| São Miguel | Azores | Portugal |
| São Tomé | Gulf of Guinea | São Tomé and Príncipe |
| Saona Island | Antilles | Dominican Republic |
Sardinia  | | Italy |
| Saria | | Greece |
Sark  | Channel Islands | Guernsey |
| Saturna | Gulf Islands, British Columbia | Canada |
| Saunders | Falkland Islands | United Kingdom |
| Sauvie | Columbia River, Oregon | United States |
| Savage | Near Islands group of the Aleutian Islands, Alaska | United States |
| Savai'i | Samoan Islands | Samoa |
| Savary | Georgia Straight, British Columbia | Canada |
| Sawyer | Mississippi River, Minnesota | United States |
| Sazan | Bay of Vlorë | Albania |
| Scarecrow | Michigan | United States |
| Scharhörn | North Sea | Germany |
| Schiermonnikoog | West Frisian Islands | Netherlands |
| Schmidt | Severnaya Zemlya, Krasnoyarsk Krai | Russia |
| Schoinoussa | Cyclades | Greece |
| School | Platte River, Nebraska | United States |
| Schouwen-Duiveland | Zeeland | Netherlands |
| Scilly | Windward Islands, Society Islands, French Polynesia | Overseas Lands of France |
| Scott | | Ross Dependency, New Zealand |
| Scott | Potomac River, Maryland | United States |
| Scotts | Kanawha River, West Virginia | United States |
| Scout | Tygart Valley River, West Virginia | United States |
| Sea | Fraser River, British Columbia | Canada |
| Seal | South Shetland Islands | Claimed by: Argentine Antarctica, Argentina,
Antártica Chilena Province of Chile, and
British Antarctic Territory of the United Kingdom |
| Sealion | Falkland Islands | United Kingdom |
| Sebatik | Sabah | Indonesia and Malaysia |
| Secretary | | New Zealand |
| Sedanka | Fox Islands group of the Aleutian Islands, Alaska | United States |
| Seguam | Andreanof Islands group of the Aleutian Islands, Alaska | United States |
| Segula | Rat Islands group of the Aleutian Islands, Alaska | United States |
| Seil | Slate Islands of the Inner Hebrides | Scotland |
| Seiland | Finnmark | Norway |
| Île de Sein | Atlantic Ocean | France |
| Sejerø | Kattegat | Denmark |
| Selaön | Lake Mälaren | Sweden |
| Selden | Potomac River, Maryland | United States |
| Selvagem Grande | Savage Islands group of the Madeira Islands | Portugal |
| Selvagem Pequena | Savage Islands group of the Madeira Islands | Portugal |
| Semisopochnoi | Rat Islands group of the Aleutian Islands, Alaska | United States |
| Semyonovsky | New Siberian Islands | Russia |
| Senja | Troms | Norway |
| Serifos | Cyclades | Greece |
| Seven | Cheat River, West Virginia | United States |
| Seven Mile | Jersey Shore, New Jersey | United States |
| Severny | Novaya Zemlya, Arkhangelsk Oblast | Russia |
| Shackleford | North Carolina | United States |
| Shanaghy | Upper Lough Erne | Ireland |
| Shandrew | Mississippi River, Illinois | United States |
| Shapinsay | The North Isles, Orkney Islands | Scotland |
| Sharp | Georgian Bay, Ontario | Canada |
| Sharp | | Hong Kong |
| Sharpes | Chesapeake Bay, Maryland | United States |
| Swan | Chesapeake Bay, Maryland | United States |
| Sharpshin | Potomac River, Maryland | United States |
| Shatvar | Persian Gulf | Iran |
| Shaw | San Juan Islands, Washington | United States |
| Shawanaga | Georgian Bay, Ontario | Canada |
| Sheek's | St. Lawrence Seaway, Ontario | Canada |
| Snead | | United States |
| Shell | | Wales |
| Shell | Florida | United States |
| Shell | Louisiana | United States |
| Shelldrake | Brockanorton Bay, Maryland | United States |
| Shemya | Semichi Islands cluster in the Near Islands group of the Aleutian Islands, Alaska | United States |
| Shenick | | Ireland |
| Shepherds | Potomac River, Maryland | United States |
| Sherbo | Atlantic Ocean | Sierra Leone |
| Sherkin | Islands of Roaringwater Bay, County Cork | Ireland |
| Sherose | Nova Scotia | Canada |
| Sherwin | Potomac River, Maryland | United States |
| Shiashkotan | Kuril Islands, Sakhalin Oblast | Russia |
| Shif | Persian Gulf | Iran |
| Shikinejima | Izu Islands | Japan |
| Shikoku | Japanese archipelago | Japan |
| Shikotan | Kuril Islands, Sakhalin Oblast | Russia, claimed by Japan |
| Shimoji | Miyako Islands part of the Sakishima Islands part of the Ryukyu Islands | Japan |
| Ship | Gulf Coast, Mississippi | United States |
| Ship | Newfoundland and Labrador | Canada |
| Shippingport | Ohio River, Kentucky | United States |
| Shoe | Beaver Island archipelago, Lake Michigan, Michigan | United States |
| Shomali | Persian Gulf | Iran |
| Shooters | Newark Bay, New Jersey | United States |
| Shortland | Shortland Islands | Solomon Islands |
| Shreves Bar | Mississippi River, Louisiana | United States |
| Shumshu | Kuril Islands, Sakhalin Oblast | Russia |
| Shuna | Slate Islands | Scotland |
| Shuwaikh | Kuwait Bay | Kuwait |
Sicily .svg.png) | | Italy |
| Sido | | South Korea |
| Sifnos | Cyclades | Greece |
| Signy | South Orkney Islands | Claimed by the United Kingdom as part of the Falkland Islands and by Argentina |
| Sijiao Island | Zhoushan Archipelago | China |
| Sikaiana | Solomon Islands | Solomon Islands |
| Sikinos | Cyclades | Greece |
| Silba | Adriatic Sea | Croatia |
| Silmido | Yellow Sea | South Korea |
| Simushir | Kuril Islands, Sakhalin Oblast | Russia |
| Sinclair | Great Barrier Reef, Queensland | Australia |
| Sinclair's Island | | Namibia |
| Sin Cowe | Spratly Islands | Disputed between: China,
Republic of China,
Vietnam,
Brunei,
Philippines, and
Malaysia |
| Sin Cowe East | Spratly Islands | Disputed between: China,
Republic of China,
Vietnam,
Brunei,
Philippines, and
Malaysia |
| Sindo | Yellow Sea | South Korea |
| Singapore | | Singapore |
| Sinjido | | South Korea |
Sint Eustatius  | Lesser Antilles | Netherlands |
| Siø | Islands of the waters south of Funen | Denmark |
| Šipan | Elaphiti Islands | Croatia |
| Sipson | Pleasant Bay, Cape Cod, Massachusetts | United States |
| Sipson Meadow | Pleasant Bay, Cape Cod, Massachusetts | United States |
| Siquijor | Visayas | Philippines |
| Sir Bani Yas | Persian Gulf | United Arab Emirates |
| Sirri | Persian Gulf | Iran |
| Sitrah | Persian Gulf | Bahrain |
| Siu A Chau | Soko Islands, Hong Kong | China |
| Sixmile | Allegheny River Pennsylvania | United States |
| Sixmile | Ohio River, Kentucky | United States |
| Sjaelland | | Denmark |
| Sjumansholmen | Southern Gothenburg Archipelago | Sweden |
| Skantzoura | Sporades | Greece |
| Skarø | Islands of the waters south of Funen | Denmark |
| Skellig Michael | Skellig Islands | Ireland |
| Skiathos | Sporades | Greece |
| Skogerøy | | Norway |
| Skopelos | Sporades | Greece |
| Skraeling | Nunavut | Canada |
| Skull | British Columbia | Canada |
| Skúvoy | Faroe Islands | Denmark |
| Isle of Skye | Inner Hebrides | Scotland |
| Skyros | Sporades | Greece |
| Slate | Slate Islands, Lake Superior, Ontario | Canada |
| Slim | Mississippi River, Missouri | United States |
| Slim | Ohio River, Kentucky | United States |
| Slipper | | New Zealand |
| Slotsholmen | Copenhagen Harbour | Denmark |
| Smaller Bent | Persian Gulf | Iran |
| Smaojlovich | Sedov Archipelago of Severnaya Zemlya, Krasnoyarsk Krai | Russia |
| Smith | Chesapeake Bay, Maryland | United States |
| Smith | San Juan Islands, Washington | United States |
| Smith | South Shetland Islands | Claimed by: Argentine Antarctica, Argentina,
Antártica Chilena Province of Chile, and
British Antarctic Territory of the United Kingdom |
| Smith | Kankakee River, Illinois | United States |
| Smokehouse | Lake Huron, Ontario | Canada |
| Smøla | | Norway |
| Smooth | Georgian Bay, Ontario | Canada |
| Snake | Black Sea | Ukraine |
| Snake | Lake Simcoe, Ontario | Canada |
| Snake | Saint Lawrence River, Ontario | Canada |
| Snake | Fishing Bay, Maryland | United States |
| Snake | Patuxent River, Maryland | United States |
| Snake | Potomac River, Maryland | United States |
| Snake | Susquehanna River, Maryland | United States |
| Snake | Georgian Bay, Ontario | Canada |
| Snape | Belcher Islands group in Hudson Bay, Nunavut | Canada |
| Snow | South Shetland Islands | Claimed by: Argentine Antarctica, Argentina,
Antártica Chilena Province of Chile, and
British Antarctic Territory of the United Kingdom |
| Soay | Inner Hebrides | Scotland |
| Soay | St. Kilda group of the Outer Hebrides | Scotland |
| Sobieszewo | Islands of Gdańsk | Poland |
| Sodo | Port Hamilton | South Korea |
| Solomons | Patuxent River, Maryland | United States |
| Solomons Lump | Kedges Straits, Maryland | United States |
| Socorro | Revillagigedo Islands, Colima | Mexico |
| Socotra | Socotra | Yemen |
| Solovetsky | Solovetsky Islands | Russia |
| Šolta | Adriatic Sea | Croatia |
| Somerset | Bermuda | United Kingdom |
| Somerset | Nunavut | Canada |
| Sondre Kvaløy | | Norway |
| Sonora | British Columbia | Canada |
| Sørøya | Finnmark | Norway |
| Sotra | Hordaland | Norway |
| Sound Gruney | Shetland Islands | Scotland |
| South | Jason Islands of the Falkland Islands | United Kingdom |
| South | | New Zealand |
| South Bass | Bass Islands, Ohio | United States |
| South Beach | Cape Cod, Massachusetts | United States |
| South Brother | Andaman Archipelago, Indian Ocean | India |
| South Brother | East River, New York | United States |
| South Brother | Chagos Archipelago, Indian Ocean | United Kingdom |
| South Brother | Atlantic Ocean, Connecticut | United States |
| South Brother | Seven Brothers, Bab-el-Mandeb | Djibouti |
| South Hammocks | Assawoman Bay, Maryland | United States |
| South Havre | Shetland Islands | Scotland |
| South Isle of Gletness | Shetland Islands | Scotland |
| South Limestone | Georgian Bay Ontario | Canada |
| South Long | | |
| South Manitou | Lake Michigan, Michigan | United States |
| South Marsh | Chesapeake Bay, Maryland | United States |
| South Monomoy | Cape Cod, Massachusetts | United States |
| South Padre | Texas | United States |
| South Ronaldsay | The South Isles, Orkney Islands | Scotland |
| South Uist | Outer Hebrides | Scotland |
| South Watcher | Georgian Bay, Ontario | Canada |
| Southampton | Nunavut | Canada |
| Southwest Cay | Spratly Islands | Disputed between:
China,
Republic of China,
Vietnam,
Brunei,
Philippines, and
Malaysia |
| Spectacle | Boston Harbor, Massachusetts | United States |
| Speedwell | Falkland Islands | United Kingdom |
| Spencer | Susquehanna River, Maryland | United States |
| Spencer | Susquehanna River, Maryland | United States |
| Spencer's | Nova Scotia | Canada |
| Sponge Bar | Willamette River, Oregon | United States |
| Spriggs | Blackwater River, Maryland | United States |
| Spring | Holland Straits, Maryland | United States |
| Spesutie | Chesapeake Bay, Maryland | United States |
| Spetses | Saronic Islands | Greece |
| Spieden | San Juan Islands, Washington | United States |
| Spiekeroog | East Frisian Islands | Germany |
| Spirit | Maligne Lake, Alberta | Canada |
| Spitsbergen | Svalbard | Norway |
| Sport-sziget | Danube River | Hungary |
| Split | Belcher Islands, Hudson Bay, Nunavut | Canada |
| Spratly | Spratly Islands | Disputed between:
China,
Republic of China,
Vietnam,
Brunei,
Philippines, and
Malaysia |
| Sprogø | Great Belt | Denmark |
| Spry | Chesapeake Bay, Maryland | United States |
| Square | Newfoundland and Labrador | Canada |
| Srednij | Sedov Archipelago of Severnaya Zemlya, Krasnoyarsk Krai | Russia |
| Sri Lanka | | Sri Lanka |
| Ssese | Lake Victoria | Uganda |
| Staats | Falkland Islands | United Kingdom |
| Stack | Mississippi River, Mississippi | United States |
| Stag | St. Clair River, Ontario | Canada |
| Stags of Broadhaven | | Ireland |
| Stall Hill | Lake Rico, Massachusetts | United States |
| Stansbury | Great Salt Lake, Utah | United States |
| Star | Isles of Shoals, New Hampshire | United States |
| Starbuck | Line Islands | Kiribati |
| Starbuck | Hudson River, New York | United States |
| Starve | Lake Erie, Ohio | United States |
| Staten | New York | United States |
| Stefansson | Nunavut | Canada |
| Stephens | Marlborough Sounds | New Zealand |
| Stevens | Lake Huron, Ontario | Canada |
| Stevens | Massachusetts | United States |
| Stewart | | New Zealand |
| Stewart | Ohio River, Kentucky | United States |
| Steels | Susquehanna River, Maryland | United States |
| Steeple | Jason Islands of the Falkland Islands | United Kingdom |
| Sterrett | Susquehanna River, Maryland | United States |
| Steves | Chincoteague Bay, Maryland | United States |
| Stingaree | Blackwater River, Maryland | United States |
| Stjernøya | Finnmark | Norway |
| Stolobny | Lake Seliger, Tver Oblast | Russia |
| Stolbovoy | New Siberian Islands | Russia |
| Stoltenhoff | Nightingale Islands, Tristan da Cunha | British Overseas Territory of Saint Helena |
| Stóra Dímun | Faroe Islands | Denmark |
| Stora Förö | Southern Gothenburg Archipelago | Sweden |
| Stor | Nunavut | Canada |
| Stora Karlsö | Baltic Sea | Sweden |
| Stord | Sunnhordland, Vestland | Norway |
| Streymoy | Faroe Islands | Denmark |
| Stromboli | Aeolian Islands | Italy |
| Strong | Pleasant Bay, Cape Cod, Massachusetts | United States |
| Stronsay | The North Isles, Orkney Islands | Scotland |
| Strynø | | Denmark |
| Stuart | Discovery Islands, British Columbia | Canada |
| Stuart | San Juan Islands, Washington | United States |
| Stucker | Susquehanna River, Pennsylvania | United States |
| Sturge | Balleny Islands | Ross Dependency, New Zealand |
| Styrsö | Southern Gothenburg Archipelago | Sweden |
| Suakin Archipelago | | Sudan |
| Sucia | San Juan Islands, Washington | United States |
| Süderoog | North Frisian Islands | Germany |
| Südfall | North Frisian Islands | Germany |
| Sue | Middle River, Maryland | United States |
| Sugar | Illinois River, Illinois | United States |
| Sugar | Michigan | United States |
| Sula | Møre og Romsdal | Norway |
| Sula Sgeir | British Isles | Scotland |
| Sulawesi | | Indonesia |
| Sumatra | | Indonesia |
| Sunhodo | Port Hamilton | South Korea |
| Suomenlinna | Gulf of Finland | Finland |
| Suðuroy | Faroe Islands | Denmark |
| Surtsey | Vestmannaeyjar | Iceland |
| Susak | Adriatic Sea | Croatia |
| Sutwik | Alaska | United States |
| Suur-Pakri | Pakri Islands | Estonia |
| Suvorov | Cook Islands | Cook Islands |
| Suwad Al Janubiyah | Hawar Islands | Bahrain |
| Suwad Al Shamaliyah | Hawar Islands | Bahrain |
| Suwanosejima | Tokara Islands part of the Satsunan Islands part of the Ryukyu Islands | Japan |
| Suwarrow | Cook Islands | Cook Islands |
| Svartsjölandet | Lake Mälaren | Sweden |
| Sveaborg | Gulf of Finland | Finland |
| Sveta Neđelja | Adriatic Sea | Montenegro |
| Sveti Andrija | Elaphiti Islands | Croatia |
| Sveti Đorđe | Bay of Kotor Islands | Montenegro |
| Sveti Grgur | Adriatic Sea | Croatia |
| Sveti Marko | Bay of Kotor Islands | Montenegro |
| Sveti Nikola | Adriatic Sea | Montenegro |
| Sveti Stefan | Adriatic Sea | Montenegro |
| Svínoy | Faroe Islands | Denmark |
| Swains | Tokelau chain, American Samoa | United States |
| Swainson | Potomac River, Maryland | United States |
| Swan | Blackwater River, Maryland | United States |
| Swan | Chesapeake Bay, Maryland | United States |
| Swan | | Honduras |
| Swan's | Maine | United States |
| Sweyn Holm | The North Isles, Orkney Islands | Scotland |
| Swindle | British Columbia | Canada |
| Switha | The South Isles, Orkney Islands | Scotland |
| Swona | The South Isles, Orkney Islands | Scotland |
| Sycamore | Potomac River, Maryland | United States |
| Sycamore | Allegheny River, Pennsylvania | United States |
| Sylt | North Frisian Islands | Germany |
| Symi | Dodecanese | Greece |
| Syrna | Dodecanese | Greece |
| Syros | Cyclades | Greece |
| Szalki-sziget | Danube | Hungary |
| Szentendrei-sziget | Danube | Hungary |
| Szúnyog-sziget | Danube | Hungary |