What makes Poseidonia's beaches stand out?
Poseidonia sits in Syros, Greece and is home to 1 ranked beach on OnlyBeaches. Every beach here is scored by the OnlyBeaches Index — a 1-10 metric blending water purity, live conditions (waves, water temperature, wind), crowd intelligence and vibe.
Whether you're after the highest-scoring beach in Poseidonia or a quieter hidden cove, the list above is refreshed every 30 minutes using live Stormglass and OpenWeather data.