Sykia is a massive open to the sky cave that you get to from the sea through a tunnel. This roofless cave is so unique, but even more special because it's so challenging to get to. You can hike (1 hour each way) or you can see it during a boat tour. However, not all tours stop for a swim here. Look for a tour to Kleftiko that has a specific stop at Sykia (and a dinghy). The boat stops at the entrance and you have to swim all the way to the shore. Once you get through it, it opens up and the rocks form a circle around you - it's almost like being inside a volcano with an opening overhead. There is a beach area inside along with a rocky area to explore.
The beach is small and pretty rocky but swimming in the cave and climbing up the whitish rocks is a great experience, just be sure to have proper shoes for it. The views and water are spectacular. Water is crystal clear with wonderful blue colors and swimming in the sea will be the highlight of your visit to Milos. Take with you, camera for pictures, water shoes for swimming to shore and climbing to overlook the pool. The snorkeling is also amazing and a unique experience here. Sykia is a must see in Milos.
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