Water policy-making requires the dedicated involvement of all stakeholders, but difficulties remain for the community sector. This study aims to examine the critical challenges of community involvement in water policy decision-making in Thailand. Both qualitative and quantitative methods used in this research project consisted of 39 interviews with informants from a variety of interested parties and 403 community members from around the East Coast River Basin in Thailand completing a survey questionnaire. The results have shown that although mechanisms to enable community involvement in decision-making, such as public consultation and water-related committees, exist, problems remain within the community sector. The critical challenges lie in the opportunities of being consulted and the sharing of power in water policy-making. Although the networks are important, at the same time, they are also obstructing the community sectors in linking their requirements to a final decision, as well as dealing with politics, policy-makers, and staff who organized the process. Therefore, the government should further develop water committee mechanisms by setting up a comprehensive yet practically easy consultation process so that new or inexperienced community members get an opportunity to practice and learn the vital elements necessary in water policy-making. Further research should be conducted in order to compare the opportunities in water decision-making between communities in rural and urban areas. Studies at the local government level should be carried out, with results used as a mechanism to enable community involvement at higher levels of water policy decision-making.