In the first quarter of 2020, the doors of museums around the world shut and their operations at physical sites were reduced in line with necessary security measures. This heralded the beginning of an uncertain future for museums and galleries as the COVID-19 pandemic hit and the only means to stay ‘open’ was to turn towards the digital. In this paper, we investigate how the physical closure of museum buildings due to lockdown restrictions caused shockwaves within their digital strategies and changed their data practices potentially for good. The methodology of the research involves a review of the impact of COVID-19 on the museum sector, based on literature and desk research, with a focus on the implications for three museums and art galleries in the United Kingdom and the United States, and their mission, objectives, and digital data practices. We also present analysis of ten qualitative interviews with expert witnesses working in the sector, representing different roles and types of institutions, undertaken between April and October 2020. Our research finds that digital engagement with museum content and practices around data in institutions have changed and that digital methods for organising and accessing collections for both staff and the general public have become more important. We present evidence that strategic preparedness influenced how well institutions were able to transition during closure and that metrics data became pivotal in understanding this novel situation. Increased engagement online changed traditional audience profiles, challenging museums to find ways of accommodating new forms of engagement in order to survive and thrive in the post-pandemic environment. Our findings point to a longer term shift in the operating models for museums and the need to realise economic value and diversify income streams through digital means, which have not yet been clearly established. The research suggests that the unprecedented situation brought on by the pandemic will shape future museum audiences and their interactions with institutions virtually and physically, posing challenges to museums and their constituents that require structural changes and adaptations, but also present opportunities to successfully survive in an ever-more connected world.