Research on social isolation and loneliness has largely overlooked refugees, who are among the loneliest in society. This study employs the COVID-19 pandemic as a natural experiment to examine how stable and situational social isolation contribute to loneliness. Drawing on two-wave panel data from 647 Syrian refugees in the Netherlands, fielded before and during the pandemic, we explore the stability of social ties across geographical and ethnic dimensions and how fluctuations lead to varying degrees of loneliness. While transnational ties served as a social safety net against loneliness during situational social isolation, our findings underscore their limited effectiveness compared to the more transient but protective local ties. Refugees who lacked local ties or experienced a disruption in local inter-ethnic ties were particularly vulnerable to heightened loneliness, emphasizing the importance of maintaining geographically close ties.