S
- Saint Marie: a fictional Caribbean island featured in Death in Paradise. It is implied that the island is either a British protectorate or a Crown Colony.
- Saint Honoré: a fictional Caribbean island featured in Agatha Christie's novel A Caribbean Mystery
- San Esperito: an island nation from Just Cause
- San Lorenzo: the setting for much of Kurt Vonnegut's novel Cat's Cradle
- San Monique: the setting of the James Bond film Live and Let Die
- San Piedro Island, Washington: from the novel Snow Falling on Cedars by David Guterson
- San Serriffe: April Fools' Day joke, The Guardian
- Sand Island: from the video game Ace Combat 5: The Unsung War
- Sandy Island
- Scabb Island: an anarchic pirate island in the Caribbean in the game Monkey Island 2: LeChuck's Revenge
- Scheria: island in Homer's Odyssey, where Odysseus meets Nausicca and Alcinous.
- Seal Island: The Suite Life on Deck
- Seven Bay Island: an island off the coast of the Northeastern United States, in the Austin family series of books by Madeleine L'Engle. Setting of the novel A Ring of Endless Light.
- Sevii Islands: a region in the fictional Pokémon universe, introduced in the Pokémon FireRed and LeafGreen video games
- Shadow Moses Island: from Metal Gear Solid video game
- Sheena Island: from the game Resident Evil Survivor
- Ship-Trap Island: the setting of Richard Connell's story The Most Dangerous Game
- Shipwreck Island: the meeting place of the Brethren Court in Pirates of the Caribbean: At World's End.
- Shutter Island: the setting of the movie, directed by Martin Scorsese, entitled Shutter Island
- Sinnoh
- Skira: an island near China and Russia that is occupied by the People's Liberation Army in the game Operation Flashpoint: Dragon Rising
- Skull Island: the island King Kong is from, also a duck-shaped island in the computergame The Curse of Monkey Island
- Sky Island: a flying island, setting for Sky Island by L. Frank Baum
- Island of Sodor: between England and the Isle of Man, the setting for the Reverend Awdry's Thomas the Tank Engine railway network managed by "The Fat Controller"
- Southern Mauristemo Islands: an internet hoax
- Spidermonkey Island: a floating island in Hugh Lofting's The Voyages of Doctor Dolittle
- Spoon Island: home of Wyndemere Castle, across the harbor of Port Charles, New York (fictional city), fictional island on the soap opera General Hospital.
- Starfish Island: from Grand Theft Auto: Vice City and Grand Theft Auto: Vice City Stories
- Sula: a Scottish island featuring in an eponymous series of children's books by Lavinia Derwent
- Sunda: a former Dutch colony, neightboring Indonesia but not part of it, in Eric Ambler's "State of Siege" (the name "Sunda" has many real-life connotations, but is not in reality the name of one specific island)
- Spider-Skull Island: from The Venture Bros.
- Summerisle: a fictional Hebridean island and the setting of Robin Hardy's 1973 movie The Wicker Man
- Summerset Isle: the homeland of the High Elves from Bethesda's Softworks' The Elder Scrolls
- Struay: a fictional Hebridean island, the setting of the Katie Morag series of picturebooks by Mairi Hedderwick
- Swallow, Flint, Mango & Mastodon Islands: in the children's novel Secret Water by Arthur Ransome
Read more about this topic: List Of Fictional Islands