Alien worlds are some of the most expansive and imaginative settings in science fiction, where unfamiliar environments, strange ecosystems, and unknown civilisations push storytelling beyond the limits of reality. From the harsh deserts of Arrakis in Dune to the shifting cultural landscapes of The Left Hand of Darkness, these worlds are not just backdrops — they actively shape conflict, identity, and survival. The unknown becomes a driving force, where discovery and danger exist side by side. This collection of 70 Alien Worlds Writing Prompts explores distant planets, strange realities, and encounters with the truly unfamiliar. With plot hooks, opening lines, character ideas, and atmospheric settings, these prompts are designed to help you build immersive sci-fi stories grounded in wonder, tension, and exploration