| Proctor | Wm. | Clarence, Denmark | PP9 | 1924 |
| Proctor & Son | O. & E. J. | Plantagenet Locs. 3622, 5089, Denmark | 4PK and 111B, 8E | 1962 |
| Properjohn | C. E. | Commonage, Katanning | CP3 | 1912 |
| Properjohn | C. E. | Commonage, Katanning | CP3 | 1924 |
| Proser | A. J. | Mayfield, Gin Gin | 2PJ | 1924 |
| Prosser | Alex | The Bone Yard and Happy Valley, Bunbury | AP3 | 1912 |
| Prosser | Alex | The Bone Yard and Happy Valley, Bunbury | AP3 | 1924 |
| Prosser | Allen C. | Prospect Hill, Woodanilling | 8AP | 1924 |
| Prosser | B. N. | Kaybrian, Kukerin | B9P and 67B, 24A | 1962 |
| Prosser | C. A. | Lorraine, Marracoonda, via, Katanning | 4CP and 50B, 21E | 1962 |
| Prosser | H. J. & L. V. | Montrose, Wickepin | I9P and 4B, 49A | 1962 |
| Prosser | Hy. | Commonage, Wickepin | PR0 | 1912 |
| Prosser | Hy. | Commonage, Wickepin | PR0 | 1924 |
| Prosser | K. A. & H. | Riverside, Cranbrook | PK2 and 38B, 36A | 1962 |
| Prosser | L. C. H. & F. D. | Culburra Downs, Waroona | L8P and 103D, 20E | 1962 |
| Prosser | N. R. | Loc. 13973, Moulyinning | 4HY and 12C, 17E | 1962 |
| Prosser | R. W. | Marracoonda, Katanning | AP3 and 4C, 3A | 1962 |
| Prosser | R. W. & G. M. | Williams Loc. 13908, dellyanine, via Wagin | R4P and 7B, 50A | 1962 |
| Prosser | T. J. | Glencoe Farm, Woodanilling | T9P | 1912 |
| Prosser | T. J. | Glencoe Farm, Woodanilling | T9P | 1924 |
| Prosser | Thos. | Glen Gile, Mt. Kokeby | TP8 | 1912 |
| Prosser | Thos. | Glen Gile, Mt. Kokeby | TP8 | 1924 |
| Prosser | W. T. | Rathmines, East Bunbury | PW5 | 1962 |
| Proud | H. F. | 17663-5, 14464, Kulin | XP5 and 10B, 24E | 1962 |
| Proud | Henry | Eversleigh Farm, Gnarming | XP5 | 1924 |
| Prouse Bros. | - | Wallatin, Geraldton | F0X | 1912 |
| Prouse Bros. | - | Avon Park, Near Doodlakine | P1B | 1912 |
| Prouse Bros. | - | Avon Park, near Doodlakine | P1B | 1924 |
| Prout | A. F. | Petravale, Ferguson | 2PF | 1962 |
| Prout | A. F. | Brooklawn, Ferguson | HS2 and 26B, 33E | 1962 |
| Prout | A. J. | The Morrells, Doodlakine | 1JP and 33B, 110A | 1962 |
| Prout | F. R. | Strathavon 683, 359, Dardanup | 4PF | 1962 |
| Prout | Geo. Ed. | Slaughter Yards, Southern Cross, Box 32, Fremantle | PE6 | 1924 |
| Prout | W. J. | Pt. Loc. 568, Dardanup | 9WP | 1962 |
| Prowse | A. W. | Wandene, Balingup | 2PA and 22C, 24E | 1962 |
| Prowse | B. W. | The Grange, Rivervale, Capel | BP5 and 43C, 30E | 1962 |
| Prowse | Benj. Wylie | Yokanup Farm, Capel | BP5 | 1924 |
| Prowse | J. M. | Wyadup Valley, Yallingup | 1WV and 41B, 24A | 1962 |
| Prowse | K. I. | Wattle Hill and Kentucky, Capel | KP3 and 120B, 22A | 1962 |
| Prowse | W. B. W. & H. G. | Highland Valley Hillcrest, Burekup and Doodlakine | B1P and 33D, 118E | 1962 |
| Prowse & Co. | - | Tachbrook, Darkan | T1N and 14B, 44A | 1962 |
| Prowse Bros. | - | Wallatin, Geraldton | F0X | 1924 |
| Pruden | C. | Lowlands, Corrigin | 8CP and 43C, 18A | 1962 |
| Pruden | R. A. | Yarabah, Mundijong | RA0 and 12B, 29A | 1962 |
| Prunster | Augustine | Indialla Cave Farm, Wagin East | A7P | 1912 |
| Prunster | Augustine | Indialla Cave Farm, Wagin East | A7P | 1924 |
| Prunster | J. H. & S. J. | Maitland Farm, York | 9QP and 21C, 24A | 1962 |
| Prunster | Joseph H. | York, York | 9QP | 1925 |
| Pryce | J. W. | Plantagnet 5213, Narrikup | PY7 | 1962 |
| Pryor | F. E. | 8147, 17868, 6701, Goomalling | P3E and 40D, 116E | 1962 |
