Following Turkey's 2020 decision to revoke border controls, many individuals journeyed towards the Greek, Bulgarian, and Turkish borders. However, the lack of verifiable statistics on irregular migration and discrepancies between media reports and actual migration patterns require further exploration. The objective of this study is to bridge this knowledge gap by harnessing novel data sources, specifically mobile phone and Twitter data, to construct estimators of cross-border mobility and to cultivate a qualitative comprehension of the unfolding events. By employing a migration diplomacy framework, we analyse emergent mobility patterns at the border. Our findings demonstrate the potential of mobile phone data for quantitative metrics and Twitter data for qualitative understanding. We underscore the ethical implications of leveraging Big Data, particularly considering the vulnerability of the population under study. This underscores the imperative for exhaustive research into the socio-political facets of human mobility, with the aim of discerning the potentialities, limitations, and risks inherent in these data sources and their integration. This scholarly endeavour contributes to a more nuanced understanding of migration dynamics and paves the way for the formulation of regulations that preclude misuse and oppressive surveillance, thereby ensuring a more accurate representation of migration realities.