Internet search data may reveal people’s intentions to migrate, as aspiring migrants tend to use online search engines to explore migration opportunities. However, unlike official migration statistics, search data may only reflect the behavior of a self-selected subset of the population, raising concerns about its generalizability. This article integrates traditional survey data - Gallup World Poll (GWP) - with Google Trends, search engine market share, and internet adoption rate to examine the extent to which search trends of migration-related topics can serve as proxies for migration intentions. The results reveal that, on a global scale, passport-related search queries strongly correlate with individuals’ intentions to migrate. However, at the country level, particularly in the global south, migration intentions are more accurately predicted by the adoption rates of Google search rather than search topics per se. These findings underscore the importance of detecting and correcting user selection biases when leveraging digital trace data for migration research, ensuring robust and representative insights into the spatial-temporal patterns of human mobility.