In 1900, a site on the western corner of Mill Point Road, then known as Suburban Road, was set aside. In June, a contract was awarded to F. S. Warner for 939 pounds. The total cost of the facility was 1,764 pounds ($3,528) when completed in 1901 and included quarters for the post mistress, by then, Miss J. Benson. Responsibility for providing the post office buildings until 1901 also rested with the State Government. Accordingly, the design and construction was undertaken by the Public Works Department (PWD) of WA. A common practice, following re-organisation of the Department in 1897, was to facilitate the works by adapting a standard design as necessary, with a site plan specifically addressing the site conditions. There is evidence that this practice was adopted in the case of the South Perth Post Office and Quarters. The standard design apparently adopted for this purpose was PWD Standard Plan Class D. Modifications probably included the substitution of the operating room for a bedroom, with the internal kitchen, pantry and laundry added at the rear. Warwick Broomfield, a reviewer of post office plans in WA suggests: "...a sheet showing a standard design which is similar to South Perth is ascribed to Hardwick in 1897". The design style is best categorised as a very simple form of Federation Bungalow as described in, but with no outstanding design elements evident. At present, the location of other buildings to the same or similar plan is not known. In 1900, J. H. Grainger was the Principal Architect, with Hillson Beasley his Chief Draughtsman. Beasley signed the Site Plan on 11 April 1900.
