Lifestyle is the first-line treatment for women with polycystic ovary syndrome (PCOS). This study examines the physical activity (PA) levels and sedentary behaviours of women with and without PCOS, and their alignment with the PCOS PA guideline.This cross-sectional study on women (aged 22-27 years) in the Australian Longitudinal Study on Women's Health was conducted in 2019 using data collected in 2017. Self-reported PA levels and total daily sitting time (ST) of women with (n=7051) and without (n=796) self-reported PCOS were presented, stratified by body mass index (BMI) and a combined overweight/obese group.71.0% and 56.7% the entire study cohort achieved PA levels recommended for weight maintenance and weight loss respectively. Overall, PA levels were lower and ST was higher in women with than without PCOS. In each BMI category, similar proportions of women with and without PCOS met the PA guidelines but became lower as BMI category increased. Fewer overweight/obese group women with than without PCOS aligned with recommendations for weight maintenance (58.7% vs 65.7%, p=0.003) or weight loss (45.1% vs 50.3%, p=0.032). ST ≥8 hours/day was observed in two-thirds of women with and without self-reported PCOS similarly before and after stratifying by BMI.High sedentary behaviour was extremely prevalent. Although the majority of women met PA recommendations for weight maintenance, only one in two overweight/obese women met PA recommendation for weight loss. Overweight/obese women with PCOS were more likely to participate in insufficient PA and require increased support to achieve sustainable healthy lifestyle.