Kastelli: This is one of my favourite spots in the Greek islands and one of the most photogenic ones, in my opinion. Imagine a small, secluded beach with an arc, beautiful waters and absolute privacy. It’s accessible only by sea but it’s really close to the port of Pano Koufonissi, despite being in the Kato.

It’s located on the northern side of Kato, kind of hard to spot, which is why it is never crowded. You can ask the traditional boat owners to take you there from the port of Pano Koufonissi and it takes around 5 minutes.
However, bear in mind that almost no boat can’t dock on that beach because the water is shallow, which means that you will have to dive around 20-30 metres away from the shore and swim to the beach if you wish to explore it.

And here's one last tip: make sure you're wearing sandals or sea shoes if you decide to walk on the pebbles, as they hurt the feet!