Undocumented migrants, known for their particularly vulnerable living conditions, were deeply affected by the COVID-19 pandemic. Despite the challenges, some demonstrated resilience, successfully remaining in their host countries. Drawing on insights from the Parchemins study, which examined the experiences of undocumented and newly regularized migrants in Geneva, Switzerland, this paper details on undocumented migrants that faced accumulated difficulties during different moments of data collection amid the pandemic. Based on empirical findings, we observe that only a specific group among undocumented migrants continued to participate in the study post-pandemic. This paper undertakes a comparative analysis of “remainers” and those who dropped out. This indicator serves as a proxy for understanding resilience among the most vulnerable in times of crisis. Through regression models, we identify the factors influencing the likelihood of remaining in the panel as undocumented even in the face of a major crisis that negatively impacted various life domains. Our analysis reveals that the chance of remaining in Geneva amidst the pandemic was influenced by solidarity bonds, prior migration experience, as well as income developments and housing situations.