In June 1905 he moved to Perth where he initially joined architects M. F. Cavanagh & Austin Bastow and later Oldham, Boas, Ednie-Brown & Partners with whom he stayed for many years.
On 29 March 1911 Boas married Sadie ("Sarah") Cohen at the Brisbane Street Synagogue in Perth.
[3] With his partners, Boas designed many public and private buildings around Perth including the open-aired King's Picture Theatre (1905), the Nedlands Park Hotel (1907), Radio station 6WF (1924), Edith Dircksey Cowan Memorial (1934), the Emu Brewery (1938),[4] the Adelphi Hotel, London Court (1937), the Gledden Building (1938) and Temple David (1954, 1963, 1973).
In 1932 Boas stood unsuccessfully for the Western Australian Legislative Council as an anti-secessionist candidate during the debate prior to the 1933 secession referendum.
He founded and edited the Australian Jewish Outlook, a short lived anti-Zionist monthly, in May 1947.