Kleftiko is a dramatic sea cave complex on the southwest coast of Milos, reachable only by boat. The white limestone cliffs rise directly from the sea, riddled with caves and arches large enough to swim or kayak through. The water inside the caves is a vivid turquoise, lit from below through submerged passages, and the snorkelling is excellent — the rock formations continue underwater and the visibility in the sheltered bays is often exceptional. Several of the caves are large enough for small boats to enter.
Every boat tour from Adamas stops here, and the main swimming area can be crowded at midday in summer. The standard tours allow an hour or more for swimming, which is enough to explore the main formations. Independent boat hire from Adamas or Pollonia gives you more flexibility to arrive early or stay late. The sea conditions around the southwest tip of the island can be rough when the meltemi is blowing hard, and trips are occasionally cancelled — check with your operator the evening before if you are travelling in July or August.