Home Postcodes by state VIC 3931 Postcode 3931 3931 is the postcode for Mornington, VIC. Localities with postcode 3931MorningtonVIC Postcode 3931 State or territory Victoria (VIC) Localities 1 Council area Mornington Peninsula Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 3930 · Postcode 3933