Jean Oldroyd had the following podium finishes at major championships: 1st in the 1958 British Empire and Commonwealth Games 4×110 yards Medlay Relay (with Anita Lonsbrough, Margaret Edwards, and the non-Olymian Anne Marshall). In the 1958 British Empire and Commonwealth Games 110 yards butterfly Oldroyd finished fifth. In the British Empire and Commonwealth Games she competed for England.
|1960 Summer||17||Roma||Swimming||Women's 100 metres Butterfly||Great Britain||GBR||4 h1 r1/2|
|1960 Summer||17||Roma||Swimming||Women's 4 × 100 metres Medley Relay||Great Britain||GBR||5||OR|
|1960 Summer||17||Roma||Swimming||Great Britain||Round One||Heat One||4||1:14.2|
|1960 Summer||17||Roma||Swimming||Great Britain||GBR||Round One||Heat One||1||QU/OR||4:49.0||1:13.2||3:45.9|