Kalo Nero or Kalonero (Greek: Καλό Νερό or Καλόνερο meaning "good water") is a village and a community of the Trifylia municipality, Messenia, southern Greece.

The population of the community is 559 (2021 census),[1] including the smaller settlements Ano Kalo Nero, Kakavas, Stasi Sidirokastro (Sidirokastro station, a railway halt), Marmaro and Vounaki.

Kalo Nero is situated on the Gulf of Kyparissia, a bay of the Ionian Sea.

Kalo Nero is a railway junction where the line from Patras and Pyrgos in the north branches to the terminus station of Kyparissia to the south and towards Kalamata via Zevgolatio in the east.

Kalo Nero has a 20 kilometre sandy beach which attracts a moderate amount of bathers in the summer months, both Greeks and foreign tourists.