Two low Cycladic islands, a 200-metre strait and Keros form a compact but unequal island system.
References checked: . The geography, archaeological and local-tradition references were read again. The narrative, local observations and travel advice remain. This records source reading, not confirmation of this year’s festival programme, menus, museum display or boat services; check those for your travel dates.
Official geographic material describes Ano and Kato Koufonisi as separate islands divided by a strait about 200 metres wide at its narrowest point. Ano is inhabited and carries the main visitor base; Kato has no permanent population.
Sea and rain have eroded the islands’ limestone into caves, hollows and pale coastal formations. The beach sequence is therefore part of the same geological system as the natural pools and sea caves.
Keros lies within the same small-island field and gives the landscape exceptional archaeological weight. It should be understood as a protected archaeological presence, not simply another casual beach stop.