Home Postcodes by state VIC 3911 Postcode 3911 3911 is the postcode for 2 localities in VIC: Baxter and Langwarrin South. Localities with postcode 3911BaxterVICLangwarrin SouthVIC Postcode 3911 State or territory Victoria (VIC) Localities 2 Council area Mornington Peninsula; Frankston Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 3910 · Postcode 3912