Small-scale in-land fishermen are one of the most vulnerable communities because of their uncertain income. However, fishermen could prosper if they have good control over their livelihood capitals. The study aims to measure the effect of livelihood capitals on the level of livelihoods’ performances using a sustainable livelihood framework approach. Respondents of the study were 90 persons (N=90) in Ca Mau Province, Vietnam. The result showed that livelihood variation of communities was low, at 5,851 USD.household-1.year-1 , with 62.4% of earnings contributed from key activity. Human capital was relatively poor with a low educational level but long experience (24.2±8.7 years). Natural capital includes wetlands and natural freshwater fish. While wetland provides wide fishing ground for fishers, natural freshwater fish stocks are degrading. The physical capital, including fishing gear and boats/motorcycles serving for fishing, was well equipped. The financial access ability was very limited. Social capital helps fishermen have high involvement with social-political organizations. The number of laborers, fishing area, net usage for fishing, number of income sources, and number of captured species influenced significantly their annual income. Overall, the livelihood of fishing households is very unsustainable. Sustainable livelihood strategies should focus on vocational training, and farming object variation to create livelihood diversity and support in terms of policies and management mechanisms.