The transition from SAP ECC (ERP Central Component) to SAP S/4HANA represents one of the most significant transformations in the SAP ecosystem. As SAP phases out mainstream maintenance for ECC, organizations worldwide are moving toward S/4HANA to leverage real-time analytics, simplified data models, and enhanced business processes. At the heart of this transformation lies data migration, a critical and complex process that determines the success of the overall S/4HANA conversion. This article explores the importance, approaches, tools, challenges, and best practices involved in data migration from SAP ECC to SAP S/4HANA.