| Sinclair | S. W. | Mervyn Street | Studebaker | N 76 | Northam Municipality | 1924-25 |
| Sinclair | S. W. | Mervyn Street | Studebaker | N 76 | Northam Municipality | 1925-26 |
| Sinclair | S. W. | Mervyn Street | Studebaker | N 76 | Northam Municipality | 1926-27 |
| Sinclair | S. W. | Mervyn Steer | Studebaker Truck | N 76 | Northam Municipality | 1927-28 |
| Sinclair | T. | Fitzgerald Street | Ford 20 H.P. | N 45 | Northam Municipality | 1916 |
| Sinclair | W. | 15 Wilberforce Street, Mount Hawthorn | Chevrolet | 15920 | Metro Private Car | 1927-28 |
| Sinclair & Hembury | - | 185 Lake Street, Perth | Chevrolet | 11897 | Metro Private Car | 1927-28 |
| Sindupp | H. | 18 Rathay Street, Victoria Park | Overland | 8413 | Metro Private Car | 1926-27 |
| Singe | W. | 91, Guildford Road, Mount Lawley | Cadillac | 3180 | Metro Private Car | 1924-25 |
| Singe | W. | 91, Guildford Road, Mount Lawley | Cadillac | 3180 | Metro Hire or Trade | 1925-26 |
| Singe | W. J. | 407 Murray Street | Harley 7 H.P. | P 456 | Perth Municipality | 1915 |
| Singe | W. J. | 407 Murray Street | Harley 7 H.P. | P 456 | Perth Municipality | 1915 |
| Singe | W. J. | Traylen Road | - | BW 2 | Bayswater Road Board | 1916 |
| Singe | W. J. | Bayswater | Studebaker 30 H.P. | P 139 | Perth Municipality | 1916 |
| Singe | W. J. | 91, Guildford Road, Mount Lawley | Studebaker 35 H.P. | P ● 139 | Perth Road Board | 1917-18 |
| Singe | W. J. | 91 Guildford Road, Mount Lawley | Hudson 29 H.P. | P 10 | Perth Municipality | 1919 |
| Singe | W. J. | 91 Guildford Road | Studebaker 20 H.P. | P 139 | Perth Municipality | 1919 |
| Singe | W. J. | 91, Guildford Road, Maylands | Mercedes | 3653 | Metro Hire or Trade | 1924-25 |
| Singe | William | 91 Guildford Road, Mount Lawley | Studebaker | 3180 | Metropolitan Hire and Trade Cars | 1923-24 |
| Singe | Wm. J. | Traylen Road, Bayswater | Studebaker 20 H.P. | P 139 | Perth Municipality | 1917-18 |
| Singer Sewing Machine Co | - | 633 Hay Street, Perth | Ford Wagon | 9159 | Metro Private Car | 1926-27 |
| SInger Sewing Machine Co | - | 633 Hay Street, Perth | Ford Wagon | 9159 | Metro Private Car | 1927-28 |
| Singer Sewing Machine Co | - | 840a Hay Street, Perth | Chevrolet Wagon | 14238 | Metro Private Car | 1927-28 |
| Singer Sewing Machine Co Ltd | - | 652 Hay Street, Perth | Ford | 4874 | Metro Private Car | 1923-24 |
| Singer Sewing Machine Co Ltd | - | 653 Hay Street, Perth | Ford | 4874 | Metro Private Car | 1924-25 |
| Singer Sewing Machine Co Ltd | - | 653 Hay Street, Perth | Ford | 4874 | Metro Private Car | 1925-26 |
| Singer Sewing Machine Co Ltd | - | 653 Hay Street, Perth | Ford | 4874 | Metro Private Car | 1926-27 |
| Singer Sewing Machine Co Ltd | - | 653 Hay Street, Perth | Ford | 4874 | Metro Private Car | 1927-28 |
| Singer Sewing Machines Co | - | 633 Hay Street, Perth | Ford Wagon | 9159 | Metro Private Car | 1925-26 |
| Singerfields | J. | Collie | Thornycroft Truck | CM 35 | Collie Municipality | 1927-28 |
| Singh | Indar | Yarloop | Buick | H ● 77 | Harvey Road Board | 1927-28 |
| Singh | R. | Dongara | Ford | IR ● 21 | Irwin Road Board | 1925-26 |
| Singh | R. | Dongara | Ford | IR ● 21 | Irwin Road Board | 1926-27 |
| Singh | R. | Dongara | Ford | IR ● 21 | Irwin Road Board | 1927-28 |
| Singleton | G. F | Wanneroo | OverlandWagon | WN ● 24 | Wanneroo Road Board | 1926-27 |
| Singleton | G. F. | Wanneroo | Overland Wagon | WN ● 24 | Wanneroo Road Board | 1927-28 |
| Singleton & Pitman Builders Exchange | - | Perth | Chevrolet | 2613 | Metro Private Car | 1927-28 |
| Sinnott | H. T. | Scotts Brook | Overland | BU ● 11 | Upper Blackwood Road Board | 1927-28 |
| Sinnott | W. P. | Scotts Brook | Overland | BU ● 11 | Upper Blackwood Road Board | 1924-25 |
| Sinnott | W. P. | Scotts Brook | Overland | BU ● 11 | Upper Blackwood Road Board | 1925-26 |
| Sinnott | W. P. | Scotts Brook | Overland | BU ● 11 | Upper Blackwood Road Board | 1926-27 |
| Sinnott | W. P. | Scotts Brook | Overland Truck | BU ● 101 | Upper Blackwood Road Board | 1926-27 |
| Sinnott | W. P. | Scott's Brook | Overland Truck | BU ● 101 | Upper Blackwood Road Board | 1927-28 |
| Sinton | L. | 42 Wood Street, Swanbourne | Chevrolet | 1527 | Metro Private Car | 1927-28 |
| Sioss | S. | Bruce Rock | Bean Truck | BK ● 266 | Bruce Rock Road Board | 1927-28 |
| Sipe | S. G. | Bruce Rock | Essex | BK ● 129 | Bruce Rock Road Board | 1924-25 |
| Sippe | S. G. | Bruce Rock | Essex | BK ● 129 | Bruce Rock Road Board | 1925-26 |
| Sippe | S. G. | Bruce Rock | Essex | BK ● 129 | Bruce Rock Road Board | 1926-27 |
| Sister | G. | Mundijong | Ford | SJ ● 143 | Serpentine-Jarrahdale Road Board | 1927-28 |
| Sith | H. J. | Gnowangerup | Ford | GN ● 126 | Gnowangerup Road Board | 1926-27 |