The most untouched beach on Mykonos — a long crescent of golden sand on the north coast with no facilities, no sun beds, no road access, and no signal. Getting here requires a 15-minute walk on a dirt track from the nearest road. The meltemi wind hits Agios Sostis hard in July and August, which discourages casual visitors and keeps the beach wild. At other times it is extraordinary: clear water, dramatic rock formations at each end of the bay, and the sense that you have the island to yourself.
The one concession to civilisation is a small snack bar that appears in high season at the top of the path. Bring water regardless. This is the beach Mykonos regulars send people to when they ask how to get away from the crowds.