The COVID-19 pandemic, and the ensuing social policies enacted to control viral transmission of SARS-CoV-2, has had a significant impact on social support networks. For people living with HIV (PWH), including gay, bisexual, and other men who have sex with men (GBMSM), social support networks serve additional purposes in the self-management of HIV care and psychosocial health. Given the broad-reaching effects of the pandemic, characterizing its impact on specific dimensions of social support networks remains a prime area of investigation. We used egocentric social network data from an on-going longitudinal study of GBMSM with HIV, living in New York City (NYC), to examine changes in the structural, interactional, and functional characteristics of their social support networks from pre- to post-start of the pandemic. We analyzed data from 146 GBMSM who reported a total of 164 social support network members. We found that the average size of social support member networks increased over time, of which 57% and 25% provided companionship and confidant support, respectively. Follow-up questions about how often guidance, tangible, and emotional support was provided (if needed) suggest the quality of support decreased over time. At follow-up, nearly half (49%) of network members were friends, the vast majority (89%) were aware of GBMSM's HIV status, and most (74%) were also living within NYC. Characterizing the changes in social support networks over the course of the COVID-19 pandemic can help identify areas of need and resilience, especially for key populations such as GBMSM with HIV.