| Summer | W. | Warren River, Katanning | 9WS | 1924 |
| Summerfield | C. A. | 1030, Witchcliffe | S4U | 1962 |
| Summerfield Farms | - | Summerfield, Koorda | RA3 and 32B, 46A | 1962 |
| Summerlea Pastoral Co. Ltd. | - | Summerlea, Capel | GD0 and 15B, 29E | 1962 |
| Summers | A. C. | Glen Hardey, Glen Forrest | WS5 and 12D, 29E | 1962 |
| Summers | E. J. | Fairfield, Capel | S0U | 1962 |
| Summers | G. L. | Stirling Estate, Capel | SU9 | 1962 |
| Summers | H. & Day, T. | Qlondong, Ballaying | D6S | 1924 |
| Summers | H. B. & J. P. B. | Swan 1345, Glen Forrest | W2C and 14B, 37A | 1962 |
| Summers | J. D. | Sunnyside, Bridgetown | 9SD | 1912 |
| Summers | J. D. | Sunnyside, Bridgetown | 9SD | 1924 |
| Summers | J. M. | Rocky Dale Farm, Karridale | MS7 and 29B, 44A | 1962 |
| Summers | James | Rose Valley, Bullsbrook | UJ3 | 1924 |
| Summers | John | Chittering Brook, Midland Junction | SJ5 | 1912 |
| Summers | John | Chittering Brook, Midland Junction | SJ5 | 1924 |
| Summers | Mrs D. | Vict. Loc. 3652, Latham | 8SU | 1924 |
| Summers | Mrs John | Bracken Capel | AN3 | 1924 |
| Summers | Mrs. John | Bracken, Capel | AN3 | 1912 |
| Summers | R. G. | Loc. 1924, Rosa Brook | YV5 | 1962 |
| Summers | W. E. | Spring Hill, Wellington Mill | S6S | 1912 |
| Summers | W. E. | Spring Hill, Wellington Mill | S6S | 1924 |
| Summers & Sons | - | 3652, 4327, 4332, 3941, 5888, 3657, Latham | 8SU and 27B, 30A | 1962 |
| Summerton | F. E. H. | Armadale, Kellerberrin | 4FE and 109B, 56F | 1962 |
| Summerton | Margaret | Crown Lands, Southern Cross | U7Z | 1924 |
| Summerton | T. G. | 6 Charles Street, Midland Junction | VV3 | 1924 |
| Sumner | Geo. | Langilowan Warren Road, Kataning | S4L | 1912 |
| Sumner | Geo. | Langilowan, Warren Road, Katanning | S4L | 1924 |
| Sumner & Sons | - | Riverbend, Dinninup | UN7 and 39B, 27E | 1962 |
| Sunder | Singh | P.O. Cranbrook | SN6 | 1912 |
| Sunder | Singh | P.O. Cranbrook | SN6 | 1924 |
| Sunmer | C. | Riverbend, Dinninup | 1LG | 1962 |
| Sunnucks | C. B. | Nicholson Downs, Cue | S4N | 1912 |
| Sunnucks | C. B. | Nicholsin Downs, Cue | S4N | 1924 |
| Sunny Crest Farm | - | Sunny Crest, Serpentine | 6LH and119B, 31A | 1962 |
| Sunny Vale Grazing Co. | - | Part Wellington Locs. 579, 207, 1522, 1981, Pt. Wellinton Loc. 219, Harvey | 8SV and 80C, 18E | 1962 |
| Sunnyside Stud | - | Sunnyside and Sunnyvale, Sawyers Valley and Beechina | S1P and 19C, 30E | 1962 |
| Sunster | Wm. | Fresh Water Camp, Sharks Bay | W4S | 1924 |
| Sunstil | W. | Mt. Pleasant, Pingelly | WT9 | 1924 |
| Sunstill | W. | Mt. Pleasant, Pingelly | WT9 | 1912 |
| Sunter | W. H. L. | Congee, Bullock Hills, via Katanning | SS1 and 12C, 23A | 1962 |
| Sunter | Walter H. L. | Ellimatto, Bullock Hills via Katanning | SS1 | 1927 |
| Sunter | Wm. | Fresh Water Camp, Sharks Bay | W4S | 1912 |
| Sunter-Smith | F. & K. | Plantagenet 5771, Albany | F2K and 32B, 8E | 1962 |
| Sunter-Smith | F. L. | Newlands, Ardath | S2F and 38D, 48E | 1962 |
| Sunvale Grazing Co. | - | 3752, Badingarra | SV7 and 103B, 37A | 1962 |
| Surman | B. J. | Lancefield Dairy, Gosnells | 0ZS | 1924 |
| Surman | H. H. | Carslisle, Armadale | 8HE | 1912 |
| Surman | H. H. | Carlisle, Armardale | 8HE | 1924 |
| Surtees & Co. | G. | Avon 20289-90, 20283/84, Gabbin | GS5 and 41B, 28E | 1962 |
| Susham | Henry | Railway View, Cuballing West | H0Z | 1924 |
