Following the rapid power shift in Damascus on 8 December 2024, the Syrian Arab Republic (henceforth referred to as Syria) is undergoing a pivotal transformation, reshaping its humanitarian, political, demographic, and recovery landscape. As a sub-component of mobility tracking, the baseline assessment provides critical data on Internally Displaced Persons (IDPs), returnees within Syria, and arrivals from abroad, whether to their place of origin or a different location. Across Syria's 14 governorates, the population landscape is shaped by significant mobility patterns. This assessment provides a comprehensive overview of mobility trends among IDPs, IDP returnees and arrivals from abroad during May 2025, as well as updated baseline figures, offering insights to support humanitarian response, and long-term reintegration efforts in Syria.