The COVID-19 pandemic has required the adoption of new precautionary health behaviours to reduce the risk of infection. This study examines adherence to four key precautionary behaviours among Canadian adults: wearing face masks, increasing the frequency of hand washing, practicing social distancing, and avoiding large crowds. Data are drawn from the Canadian Perspective Survey Series 3: Resuming Economic and Social Activities During COVID-19, administered by Statistics Canada in June 2020. Weighted descriptives calculate overall adherence levels and logistic regressions models of each behaviour as a function of demographics and socioeconomic status identify vulnerable segments of the population. We find a nearly universal increase in hand washing (94%) and high adherence to social distancing and avoiding crowds (82% and 84% respectively). Adherence to the use of face masks is much lower (67% on average); moreover, there are significant disparities in their use. Women, older adults, immigrants, and urban residents are much more likely to adhere to mask wearing, and other precautionary behaviours, than men, younger adults, Canadian-born, and rural residents. Canadian adults with a university degree are also the most likely to wear face masks and avoid large crowds. The most significant disparities in the use of COVID-19 precautions are found across demographic characteristics. These estimates have substantial implications for policy and potential public health interventions.