The world today is rapidly changing at an exponentially growing rate. When the speed of change became recognized, businesses have transformed themselves accordingly. Globalization combines the business activities of all kinds of organizations to become one market to pick up changes. Supply chain management, as a group of organizations that builds connections and establishes material and information flows in order to deliver goods and/or services, has become a major source of competitive advantage to companies in becoming borderless. This study aims to explore the key success factors for of information flow for EDI along the supply chain for the organization to improve the performance and power of information flow. Case study methodology is used for interviewing fifteen senior managers of the Electricity Generating Authority of Thailand (EGAT). The study found communication and collaboration, knowledge sharing, work skill development, policy and regulation, hierarchy of the organization, research development, innovation, and technology development, generation gaps, information management, mobile application, and prepare for the changes, as the key success factors of information flow for their organization. The results can be analyzed to plan or adjust strategy, and adapt to the changes of new technology in the competitive environment. Moreover, the results can assist managers in similar industries to realize the key success factors of information flow for EDI along the supply chain management for better performance.