I was at Koufonisia in April, which is not high season for this island. It was me and my boyfriend at Pori, a very long beach with no people around, which was natural for such a small and isolate place. This was our best time on Koufonisia. I hate crowded beaches and people yelling and screaming. I prefer calm beaches like Pori. I don't know how this beach would be in summer, where there will be many tourists. But in April and May, you can enjoy all the peace you want. You can do some nudism too. Do not be afraid, no one will see you. You can take the boat to go to Pori or by motorbike.