Do migrants become more anti-immigration over time? How do incumbents react to new arrivals? We link large-scale survey data to local immigration flows across 138 European regions from 2002 to 2024, identifying effects via a leave-out shift-share instrument within a triple-difference design. Immigrants arrive strongly pro-immigration, but support erodes over time, halving the native-immigrant gap within two decades. Exposure to new inflows contributes to this convergence: a rising local immigrant share reduces pro-immigration attitudes for both groups, with substantially larger effects for first-generation immigrants. Low-skilled incumbents respond more to inflow size, high-skilled to newcomers' skill composition.