Kalamaki beach is just after Cape Nisakoulia, south of Koroni (almost near Vasilitsi). It is the southernmost beach of Messenia and one of the most impressive.
Specifically, it is a beach with pebbles, sand and turquoise waters. Trees and greenery cover its northern side. It is not organised, so you should bring the essentials with you.
A hallmark of Kalamaki beach is the rusty boat, which ran aground on its shallows years ago.