Social network research has been well conceptualized in theory, but limited in practice especially for aquaculture production. This study is aimed to explore the roles of social network in extensive shrimp farming, an important rural livelihood activity in the coastal areas of Vietnam. The research was carried out in Ben Tre province using mixed approach of qualitative and quantitative by household survey (131 shrimp farmers) and in-depth interview (15 respondents). The result shows that there are many social factors existing in the rural area which can be categorized into 3 groups as family and neighbors, trading agents and formal organizations. We found that traditional culture like the family and neighbor network still plays the most important role in rural society in general and shrimp production in particular. This network can help farmers in many ways including knowledge, skill, health care, spirit, and finance. The social cohesion is also better with family and neighbor among others. Secondly, trading agents provide significant market information and input supply. The formal organizations as local extension workers, cooperatives or socio-political organizations keep less importance. Therefore, it is necessary to take into account the role of family and neighbor network and trading actors in rural development projects on one hand and enhance the role of formal organizations on the other hand.