Safe and environmentally friendly production has become an important trend in the aquaculture sector. Vietnam has successfully implemented a certified organic shrimp production project and is now planning to expand it. To successfully implement the certified organic shrimp production project in new areas, the ex ante evaluation of the factors influencing farmers’ decision to participate in this project is essential. Thus, this research determines factors affecting shrimp farmers’ decision to participate in a certified organic shrimp production project by analyzing a multinomial logit model. A survey was conducted in the Vietnamese part of the Mekong Delta and covered 220 shrimp farmers. The results show that farmers who have higher mangrove coverage in their shrimp farms are more likely to participate in the project. The likelihood of adoption also increases when farmers have a higher level of education. Interestingly, the premium commanded by the certified organic shrimp is not among the important factors affecting farmers’ decision to participate in the project.