The study examines the historical evolution of the Srivijaya Kingdom as a major maritime power and a prosperous centre in Southeast Asia from the 12th to the 19th Buddhist centuries. It focuses on Srivijaya’s political, economic, social, and cultural contributions, as well as the spread of its influence to Chaiya, Nakhon Si Thammarat, and Sukhothai. The research further relates these historical legacies to Human Security, highlighting how Srivijaya’s multicultural heritage can help reduce conflict, strengthen social cohesion, and enhance security within culturally diverse communities. Historical and developmental research methods were combined with content analysis of historical and archaeological records. In-depth interviews and focus group discussions were conducted with residents and experts across the study areas. The resulting qualitative evidence was analysed to examine Srivijaya’s historical development and the persistence of its civilizational legacy. The findings indicate that Srivijaya was more than a trading polity controlling maritime routes between India and China. It also functioned as a significant regional centre of political, religious, and cultural development. Its multicultural foundations provide a potential model for peaceful coexistence in contemporary societies, particularly in Thailand’s southern border provinces, where communities continue to face substantial human security challenges.