Home Postcode finder WA Londonderry Londonderry postcode WA Londonderry is a locality in Western Australia covered by postcode 6429. Postcode 6429 State or territory Western Australia (WA) Region Wa Subs 1 G Flds Add a free Londonderry business listing Be the first listing in Londonderry Common questionsWhat is the postcode for Londonderry?Londonderry, WA has the postcode 6429.What state is Londonderry in?Londonderry is in Western Australia (WA).Does postcode 6429 cover more than one suburb?Yes. Postcode 6429 covers 8 localities, so the postcode alone does not identify Londonderry. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.