The positive relationship between social connections and mental health and wellbeing has been widely documented. During the initial stage of the pandemic, COVID-19 associated restrictions had given rise to social isolation that had a negative effect on individuals' mental health and wellbeing, particularly among patients with preexisting mental health disorders. To abridge physical distance, digital technology had become a primary method of communication and social engagement. However, not everyone had access to internet and devices required to connect online due to the digital divide, especially among marginalized populations. The purpose of this multiple case study was to explore experiences of social isolation and the digital divide among patients with mental health disorders, and its impact on their mental health and wellbeing. Our findings revealed that social isolation was the major contributing factor to the intensification of mental health symptoms, while the digital divide (e.g., financial constraints and low proficiency in digital technology) was recognized as a barrier to making social connections via digital technologies. Nurses should engage with communities and policymakers in developing strategies to address the social determinants of health disparities during the current pandemic, other disruptive pandemics and beyond.