SS Oronsay was completed in 1951 at Vickers-Armstrong, Barrow-in-Furness, but was delivered several months behind schedule because of a serious fire that broke out in the fitting-out berth. The Oronsay operated the UK to Australasia service, via the Suez Canal. On 1 January 1954, Oronsay left Sydney on the first Orient Line transpacific voyage to Auckland, Suva, Honolulu, Victoria, Vancouver and San Francisco, returning via the same ports. In later years the transpacific sailings became a regular feature of the Orient/P&O services.
In 1960 the Orient Line and P&O fleets merged, Oronsay continued to operate under the Orient houseflag and retained her corn-coloured hull until 1964, when her hull was painted P&O white In 1966.
She was withdrawn from service, on 7 October 1975 she arrived at Kaohsiung to be broken up by the Nan Feng Steel Enterprise Co.