onslow postcode wa Home ›› Postcode Finder ›› WA ›› Onslow Onslow local listingsThe suburb of Onslow is located in WA and has a postcode of 6710. Free onslow business listing! 1Elite Maintenance PilbaraOnslow WA, Australia 1315802Onslow SchoolSimpson St 08 91846062 View more business listings in onslow Search and find other Postcodes in Western Australia or widen the search to Postcodes in Australia.