Home Postcodes by state NSW 2305 Postcode 2305 2305 is the postcode for 3 localities in NSW: Kotara East, New Lambton and New Lambton Heights. Localities with postcode 2305Kotara EastNSWNew LambtonNSWNew Lambton HeightsNSW Postcode 2305 State or territory New South Wales (NSW) Localities 3 Council area Newcastle; Mainly Lake Macquarie, partly Newcastle Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 2304 · Postcode 2306