Given the major role of workplaces as points of contamination and the traditional commitment of trade unions to uphold occupational health and safety standards, trade unions could be expected to be strongly involved in mobilising against the Covid-19 pandemic. This article focuses on their policy positions (at national and sectoral level) towards the occupational health and safety measures taken to limit the spread of Covid-19 in Germany, France and Luxembourg from the beginning of the pandemic in March 2020 until the surging fourth wave of infections in November-December 2021. Our data shows that unions have found it increasingly difficult over the course of the pandemic to develop policy positions in the domain of occupational health and safety that address the variegated situations and needs of their different member groups and that achieve a balance between membership logics and public health considerations.