Home Postcode finder QLD Gemini Mountains Gemini Mountains postcode QLD Gemini Mountains is a locality in Queensland covered by postcode 4721. Postcode 4721 State or territory Queensland (QLD) Region Central QLD Add a free Gemini Mountains business listing Be the first listing in Gemini Mountains Common questionsWhat is the postcode for Gemini Mountains?Gemini Mountains, QLD has the postcode 4721.What state is Gemini Mountains in?Gemini Mountains is in Queensland (QLD).Does postcode 4721 cover more than one suburb?Yes. Postcode 4721 covers 8 localities, so the postcode alone does not identify Gemini Mountains. Browse other postcodes in Queensland, or widen the search to every Australian postcode.