This study examines how the growing competition over immigration and welfare between social democratic parties and populist radical right parties impacts electoral outcomes. The study argues that the historical legacies of the social democratic and conservative welfare regimes influence how voters respond to this competitive struggle. The findings support this argument. In the social democratic regime, populist radical right parties gain more support when they compete over welfare, although Nordic social democratic parties can mitigate this trend by appearing tough on immigration. However, populist radical right parties’ emphasis on welfare is the main source of electoral mobilization, particularly among voters with anti-immigration sentiments. In the conservative regime, the competitive dynamic is less connected to immigration, and populist radical right parties’ welfare discourse appeals primarily to economically vulnerable voters, while social democratic parties lose votes by taking a strict stance on immigration. These results have important implications and suggest that welfare regimes shape voting behaviour differently today than in previous eras.