K
- Kanto: from the Pokémon franchise
- Karamja: from the world of Gielenor RuneScape
- Keelhaul Key: from the video game Paper Mario: The Thousand-Year Door
- Kilika: from Final Fantasy X and Final Fantasy X-2
- Kinakuta: island state in Southeast Asia of Neal Stephenson's novel Cryptonomicon. Compare Queena-Kootah in Neal Stephenson's novel The Confusion
- Kirrin Island: in the Famous Five children's books by Enid Blyton
- Kitchen Island: from the Wario Land series
- Koholint Island: from the video game The Legend of Zelda: Link's Awakening
- Kokovoko: from the Herman Melville novel Moby-Dick (Queequeq is from Kokovoko)
- Koo Koo Island: an island in the West Indies briefly mentioned in Carry On at Your Convenience
- Krawk Island: an island in Neopia
Read more about this topic: List Of Fictional Islands