Measures implemented to combat the spread of COVID-19 have included stay-at-home orders, social distancing, and self-isolation, all of which have limited in-person interactions. Given the key role of technology in maintaining social connections during this period, the current study examined the experiences of young adults who shifted from predominantly offline to online interaction with friends during COVID-19. Specifically, we investigated whether changing from interacting predominantly with friends in-person to interacting predominantly with friends online (conceptualized as a major change in context of interaction) was associated with lower social well-being (i.e., greater loneliness and lower social connectedness), and examined whether perceived changes in friendship satisfaction as a result of the pandemic mediated these effects. Participants (N = 329; 68.1% female) were Australian young adults, aged between 17 and 25 years (Mage = 20.05 years, SD = 1.97). Data were collected between April 15th and May 24th, 2020, during the nationwide lockdown in Australia. Results indicated that for young adults who primarily interacted offline with friends prior to COVID-19 (as compared to those who interacted predominantly online or equally online and offline before the pandemic), the shift away from face-to-face interactions was associated with a greater perceived reduction in satisfaction with friendships, which, in turn, was associated with greater loneliness and lower social connectedness. Our results highlight the need to consider how young adults adjust to changes in contexts for engaging with friends and how they maintain meaningful social interactions with others during times of extended physical isolation.