| Inskip | G. A. | Architect | Perth | 1887 | WA Almanack |
| Instone | & Co. | Plumbers & Tinsmiths | Croke Street, Fremantle | 1897 | Witton's Directory |
| Instone | F. | | Hill Street, Fremantle | 1897 | Witton's Directory |
| Inverarity | D. H. | Architect & Building Surveyor | Lamb Street, Perth | 1897 | Witton's Directory |
| Inverarity | Jas. | Schoolmaster | Greenbushes | 1897 | Witton's Directory |
| Inverary | J.H. | Miner | Nannine | 1897 | Witton's Directory |
| Ireland | R. | - | Howick Street, Perth | 1873 | Herald Almanack |
| Ireland | R. | - | Perth | 1874 | Herald Almanack |
| Ireland | R. | - | Perth | 1875 | Herald Almanack |
| Ireland | R. | - | Perth | 1875 | WA Almanack |
| Ironside & Co | R. | | Victoria Buildings, Bayley Street, Coolgardie | 1897 | Witton's Directory |
| Ironside & Deykin | | Surveyors & Draughtsmen | Victoria Buildings, Bayley Street, Coolgardie | 1897 | Witton's Directory |
| Irvin | J. | Pearler | Cossack | 1885 | Herald Almanack |
| Irvine | A. W. | Mine Manager | Londonderry | 1897 | Witton's Directory |
| Irvine | J. | | Essex Street, Fremantle | 1897 | Witton's Directory |
| Irvine | J. | Captain | Gray Street, Fremantle | 1897 | Witton's Directory |
| Irvine | James | | Douro Street, Perth | 1897 | Witton's Directory |
| Irvine | R. J. | | Swan Street, North Fremantle | 1897 | Witton's Directory |
| Irvine | T. | Mining Agent & Sharebroker | Sylvester Street, Coolgardie | 1897 | Witton's Directory |
| Irvine | W. | Blacksmith | Cue | 1897 | Witton's Directory |
| Irvine | W. | Miner | Golden Valley | 1897 | Witton's Directory |
| Irvine | W. T. | Accountant, Stockbrokers, Office of Westralian Premier Gold Mines, Ltd, Burbank's Birthday Gift Gold Mines, Ltd, Gladiators, Ltd | Coolgardie Chambers, Bayley Street, Coolgardie | 1897 | Witton's Directory |
| Irving | T. | Enginedriver | Karridale | 1897 | Witton's Directory |
| Irwin | Mrs. | Boarding House | Stirling Street, Perth | 1897 | Witton's Directory |
| Irytown | Jos. | Miner | Northampton | 1885 | Herald Almanack |
| Isaacs | Jno | Miner | Nannine | 1897 | Witton's Directory |
| Isaacs | Sam | Teamster | Busselton, Etc. (Augusta, Etc., Karridale, Boranup & Hamlin) | 1889 | WA Almanack |
| Isaacs | Sam. | Teamster | Busselton(Augusta) | 1888 | WA Almanack |
| Isard | George J. | Carriage Examiner | Beverley | 1897 | Witton's Directory |
| Isbeester | S. | Shipwright | Cossack | 1885 | Herald Almanack |
| Isbester | S. | Shipwright | North-West Coast - Roebourne & Cossack | 1877 | Herald Almanack |
| Isbester | S. | Shipwright | North-West Coast - Roebourne & Cossack | 1878 | Herald Almanack |
| Isbester | S. | Shipwright | Cossack | 1879 | Herald Almanack |
| Isbester | S. | Shipwright | North-West Coast (Roeburne & Cossack) | 1879 | WA Almanack |
| Isbester | S. | Shipwright | Canning | 1880 | Herald Almanack |
| Isbester | S. | Shipwright | North-West Coast | 1880 | WA Almanack |
| Isbester | S. | ShipWright | Cossack | 1881 | Herald Almanack |
| Isbester | S. | Shipwright | North-West Coast (Cossack) | 1881 | WA Almanack |
| Isbester | S. | Shipwright | Cossack | 1882 | Herald Almanack |
| Isbester | S. | Shipwright | North-West Coast (Cossack) | 1882 | WA Almanack |
| Isbester | S. | Shipwright | Cossack | 1883 | Herald Almanack |
| Isbester | S. | Shipwright | Cossack | 1884 | Herald Almanack |
| Isbester | S. | Shipwright | North-West Coast (Cossack) | 1884 | WA Almanack |
| Isbester | S. | Shipwright | North-West Coast (Cossack) | 1886 | WA Almanack |
| Isdell | F. | Miner | Nannine | 1897 | Witton's Directory |
| Isles | Miss | Dressmaker | Guildford | 1882 | WA Almanack |
| Isles | Miss | Dressmaker | Guildford | 1883 | WA Almanack |
| Isles | R. | Labourer | Guildford | 1882 | WA Almanack |
| Isles | R. | Labourer | Guildford | 1883 | WA Almanack |
| Israel & Beadell | | Farmers' Home Hotel | Bridgetown | 1897 | Witton's Directory |
