Home Postcodes by state QLD 4121 Postcode 4121 4121 is the postcode for 5 localities in QLD: Holland Park, Holland Park East, Holland Park West, Tarragindi and Wellers Hill. Localities with postcode 4121Holland ParkQLDHolland Park EastQLDHolland Park WestQLDTarragindiQLDWellers HillQLD Postcode 4121 State or territory Queensland (QLD) Localities 5 Council area Brisbane Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 4120 · Postcode 4122