| Sons of Gwalia Ltd | - | Gwalia | Overland 16 H.P. | ML 3 | Mount Malcolm Road Board | 1916 |
| Sons of Gwalia Ltd | - | Gwalia | Overland 16 H.P. | ML 4 | Mount Malcolm Road Board | 1916 |
| Sonsee | Arthur | 45 Suffolk Street | B.S.A. 3½ H.P. Motorcycle | F 121 | Fremantle Municipality | 1916 |
| Sonubert | A. | 18 Altona Street, West Perth | Essex | 13603 | Metro Private Car | 1927-28 |
| Sorensen | A. | 190 Bagot Road, Subiaco | Chevrolet | 5962 | Metro Private Car | 1927-28 |
| Sorensen | G. E. | o/o Topping Point South Fremantle | Nash | 10793 | Metro Hire or Trade | 1927-28 |
| Sorenson | E. | Gwalia | Ford | LM ● 8 | Leonora-Malcolm Road Board | 1924-25 |
| Sorenson | E. | Gwalia | Ford | LM ● 8 | Leonora-Malcolm Road Board | 1925-26 |
| Sorenson | E. | Gwalia | Ford | LM ● 8 | Leonora-Malcolm Road Board | 1926-27 |
| Sorenson | G. E. | Babakin | Hupmobile | BK ● 153 | Bruce Rock Road Board | 1924-25 |
| Sorenson | G. E. | Babakin | Summitt | BK ● 197 | Bruce Rock Road Board | 1925-26 |
| Sorenson | G. E. | Babakin | Summitt | BK ● 197 | Bruce Rock Road Board | 1926-27 |
| Sorenson | G. E. | Babakin | Summitt | BK ● 197 | Bruce Rock Road Board | 1927-28 |
| Sorfleet | C. | Carbunup | Commerce Truck | SU ● 9 | Sussex Road Board | 1925-26 |
| Sorfleet | C. | 3 Dudley Street, West Perth | Commerce | 10457 | Metro Hire or Trade | 1926-27 |
| Sorrenson | W. | Narembeen | Ford | NB ● 128 | Narembeen Road Board | 1927-28 |
| Sory | N. E. | Mandora Station, Wallal | Chevrolet | BM ● 54 | Broome Road Board | 1926-27 |
| Souchcott | O. E. | Baandee | Overland | MD ● 238 | Merredin Road Board | 1926-27 |
| Soughbridge | D. G. | Northam | Chrysler | N ● 57 | Northam Road Board | 1926-27 |
| Souires | G. J. | 148 Northwood Street, Leederville | Chevrolet | 7371 | Metro Private Car | 1927-28 |
| Soundes | W. H. | Wagin | Overland | WW56 | Wagin Municipality | 1926-27 |
| Soundes | W. H. | Wagin | Overland | WN 56 | Wagin Municipality | 1927-28 |
| Sounness | A. H. | Mount Barker | Dodge Truck | PL ● 152 | Plantagenet Road Board | 1927-28 |
| Sounness | Albert Richard. | Mount Barker | Aux. Cycle 2H.P. Motorcycle | PL ● 19 | Plantagenet Road Board | 1922-23 |
| Sounness | F. H. | Mount Barker | Buick | PL ● 65 | Plantagenet Road Board | 1927-28 |
| Sounness | G. J. | Mount Barker | Chevrolet 20 H.P. | PL ● 28 | Plantagenet Road Board | 1917-18 |
| Sounness | J. G. | Mount Barker | Chevrolet 20 H.P. | PL ● 28 | Plantagenet Road Board | 1919 |
| Sounness | J. G. | Mount Barker | Maxwell | PL ● 28 | Plantagenet Road Board | 1925-26 |
| Sounness | J. G. | Mount Barker | Chrysler | PL ● 51 | Plantagenet Road Board | 1927-28 |
| Sounness | John Grey | Mount Barker | Chevrolet | PL ● 28 | Plantagenet Road Board | 1923-24 |
| Sounness | John Grey | Mount Barker | Maxwell | PL ● 28 | Plantagenet Road Board | 1924-25 |
| Sounness | John. Grey | Mount Barker | Chevrolet | PL ● 28 | Plantagenet Road Board | 1922-23 |
| Sounness | Miss A. J. | Mount Barker | Dodge | PL ● 120 | Plantagenet Road Board | 1924-25 |
| Sounness | O. A. K. | Mount Barker | Studebaker | PL ● 83 | Plantagenet Road Board | 1924-25 |
| Sounness | O. A. K. | Mount Barker | Studebaker | PL ● 83 | Plantagenet Road Board | 1925-26 |
| Sounness | O. A. K. | Mount Barker | Studebaker | PL ● 83 | Plantagenet Road Board | 1926-27 |
| Sounness | O. A. K. | Mount Barker | Willys-Knight | PL ● 32 | Plantagenet Road Board | 1927-28 |
| Sounness | T. G. | Mount Barker | Buick | PL ● 21 | Plantagenet Road Board | 1927-28 |
| Sounness | W. and Sons | Mount Barker | Ford | PL ● 21 | Plantagenet Road Board | 1923-24 |
| Sounness | W. E. | Woogenellup | Overland 20 H.P. | PL ● 9 | Plantagenet Road Board | 1917-18 |
| Sounness | W. E. | Woogenalup | Overland 20 H.P. | PL ● 9 | Plantagenet Road Board | 1919 |
| Sounness | W. E. | King River | Dodge | A ● 12 | Albany Road Board | 1924-25 |
| Sounness | W. E. | King River | Dodge | A ● 12 | Albany Road Board | 1925-26 |
| Sounness | W. E. | King River | Dodge | A ● 12 | Albany Road Board | 1926-27 |
| Sounness | W. E. | King River | Dodge | A ● 12 | Albany Road Board | 1927-28 |
| Sounness & Son | W. | Mount Baker | Dodge | PL ● 21 | Plantagenet Road Board | 1924-25 |
| Sounness & Sons | W. | Mount Barker | Ford | PL ● 21 | Plantagenet Road Board | 1922-23 |
| Sounness & Sons | W. | Mount Barker | Dodge | PL ● 21 | Plantagenet Road Board | 1924-25 |
| Sounness & Sons | W. | Mount Barker | Dodge | PL ● 21 | Plantagenet Road Board | 1925-26 |
| Soutar | W. H. | 47 Mabel Street, North Perth | Chevrolet | 11644 | Metro Private Car | 1927-28 |
