The Sirens' Island is an island in the Sea of Monsters, where the Sirens dwell. The beach has black volcanic rock and sand with a large cove that is filled with spikes, mines, broken wood, and shredded ships from past sailors that were lured to their doom. In Greek mythology, the Sirens sing so sweetly that they enchant sailors and lure them to their deaths. The island changes appearance, though, depending on what your heart desires. In older times, it was known as "Sirenum Scopuli", meaning "Rock of the Sirens" in Latin.
After Percy Jackson and Annabeth Chase escape Circe's island, they pass the Siren's Island. Annabeth desires to hear the Siren's song, because she believes it reveals secrets about those who hear it they would otherwise never know. Annabeth knows that she would want to jump overboard and join the Sirens, so she has Percy tie her to the foremast and tells him, "Don't untie me, no matter what happens or how much I plead. I'll want to go straight over the edge and drown myself." However, before Percy ties her up, he forgets to disarm her of her celestial bronze knife, which she later uses to cut off the ropes binding her. After she escapes the ropes and jumps in the water, Percy quickly follows her and jumps out into the ocean to catch her before she reaches the Sirens and is consequently eaten.
When Percy finally catches up with Annabeth, and when he grabs her ankle to stop her, he sees everything Annabeth is visualizing. He sees Annabeth's mother, Athena, and her father at a picnic in Central Park with Annabeth and Luke. Behind the park, designed by Annabeth and built from dazzling white marble, rose a re-worked skyline of Manhattan. Percy then proceeds to pull Annabeth underwater, so that the sound would not reach her ears, breaking the spell, and he summons an air bubble to form a protective shell around Annabeth and himself to cut off the Siren's song, but also so Annabeth can breathe. When the spell of the Siren's song breaks, Annabeth starts crying.
- The original island was thought to be Capri off the coast of Italy. As Western Civilization moves, the island moves its location with it, like Mount Olympus.