This dissertation aims to examine the role that migration and the COVID-19 pandemic play in the subjective well-being (SWB) of older adults. It does so through five quantitative and qualitative research articles focusing on four populations: German and Italian migrants living in Switzerland, Swiss natives, and Italian natives. Results show that migrants report lower SWB than natives. This is due to their disadvantaged socioeconomic and health conditions, likely resulting from the accumulated challenges and limited opportunities encountered post-migration. When considering the influence of COVID-19 on individuals’ SWB, results show that transnational attachment, and particularly citizenship and voting practices, can have negative implications for migrant well-being during the pandemic. Moreover, results demonstrate that determinants of SWB differ among groups. This thesis suggests that policies aimed at easing the naturalization process may benefit ageing migrants, but also that the heterogeneity of the ageing population should be considered when implementing regulations aimed at improving well-being.