The study examined how the commodity chain of freshwater fresh fish trade between Thailand and Cambodia developed and became sex segregated, and how women small-scale traders are positioned in the chain. The open border policy increased trade and demand for fish, and made it more difficult for small-scale traders to secure fish. Lack of state control led to rent-seeking, which further closed opportunities for resourceless small-scale traders. Women small-scale border traders tried to counter the marginalization through establishing social networks, but with limited success. Field interviews with 86 traders at the border areas of Thailand and Cambodia were conducted to explore these points.