This study examines sustainable livelihood assets in 8 coastal communes of Kim Son district, Ninh Binh province, Vietnam, a coastal region reliant on both agriculture and aquaculture, using the Department for International Development’s (DFID) sustainable livelihoods framework. Household assets—natural, human, physical, financial, and social capital—were evaluated to identify optimal livelihood strategies and strengthen resilience against risks. Data were gathered via a structured survey (400 questionnaires), expert interviews, and the Analytic Hierarchy Process (AHP). The results provide sustainability indicators for each commune, identifying both strengths and areas requiring improvement to enhance local sustainability scores. The study also compares these results with the UNDP’s sustainability index, revealing that one area achieved an advanced sustainable livelihood level, while the remaining seven reached a basic sustainability level in accordance with UNDP guidelines. Highlighting variations in asset conditions, the study proposes policy directions to enhance the sustainable livelihood index, emphasizing local adaptation and resilience. This research contributes to understanding livelihood sustainability in coastal communities dependent on diverse economic activities.