The COVID-19 pandemic was in 2020 and 2021 for a large part mitigated by reducing contacts in the general population. To monitor how these contacts changed over the course of the pandemic in the Netherlands, a longitudinal survey was conducted where participants reported on their at-risk contacts every two weeks, as part of the European CoMix survey. The survey included 1659 participants from April to August 2020 and 2514 participants from December 2020 to September 2021. We categorized the number of unique contacted persons excluding household members, reported per participant per day into six activity levels, defined as 0, 1, 2, 3-4, 5-9 and 10 or more reported contacts. After correcting for age, vaccination status, risk status for severe outcome of infection, and frequency of participation, activity levels increased over time, coinciding with relaxation of COVID-19 control measures. ; Te authors would like to thank all participants of the CoMix survey. Te CoMix study in the Netherlands was made possible through funding from the European Union’s Horizon 2020 research and innovation programme— project EpiPose (Grant Agreement Number 101003688). Tis work refects only the authors’ view. Te European Commission is not responsible for any use that may be made of the information it contains. We are grateful to the EpiPose management team for coordinating the CoMix survey so data collection was made possible in the Netherlands.