Arsinoi (Greek: Αρσινόη) is a local community (topiki koinotita) of the municipal unit (dimotiki enotita) Ithomi, of the municipality (dimos) of Messini within the regional unit (perifereiaki enotita) of Messenia in the region (perifereia) of Peloponnese, one of 13 regions into which Greece has been divided.