<p>The concept of livelihood encompasses the diverse strategies individuals and households employ to meet their basic needs through economic activities, resource utilization, and various capabilities across economic, social, and environmental domains. In the context of Majuli’s char lands (mid-channel bar) in the Brahmaputra River, residents face significant socio-economic challenges exacerbated by frequent floods. This study aims to understand their realities and assess the sustainability of their livelihoods. Using a dataset of 496 randomly selected samples, the Sustainable Livelihood Security Index evaluates livelihood sustainability across five dimensions: Ecological Security Index, Economic Efficiency Index, Social Equity Index, Institutional Support Index, and Structural Outcome Index. Agricultural Land dominates the island’s landscape, with some villages showing moderate economic, social, and structural sustainability but lagging in ecological sustainability. Others, like Bor Pamua No. 1 and Borgayan No.1 Villages, exhibit lower sustainability across multiple dimensions. All villages face social deprivation due to inadequate infrastructure and services. The study’s findings highlight the need for policy interventions to enhance ecological resilience, economic efficiency, social equity, institutional support, and structural outcomes in the community. This research is novel in its focus on char land residents, filling a critical gap in the existing literature and offering valuable insights for sustainable development in Majuli.</p>