This paper is based on the water-saving initiatives for sustainable tourist destinations launched by the government sector under a project called Save Water, Save Samui (SWSS) at Samui Island, a famous tourist destination in Thailand. For this project, a mixed-methodologies research approach was employed. This research aims to identify stakeholder engagement processes for water-saving initiatives. Quantitative research methods were conducted through a questionnaire-based survey, which provided supportive information from guests and hotels voluntarily involved in the SWSS project. Qualitative research methods were conducted through focus group discussions with hotel staff and in-depth interviews with representatives from hotel businesses, government officers, and locals. Findings showed that stakeholder engagement processes in the SWSS project appeared at three levels: information, response, and involvement. Lessons from the SWSS project addressed limiting aspects of the stakeholder engagement processes, including poor information dissemination, small numbers and few stakeholders involved, inconsistency across the project, and unclear incentive strategies for stakeholder engagement. To move forward, establishing a collaborative relationship among stakeholders is required to facilitate network extension, with the goal of an inclusive and collective action strategy to pursue water saving for tourist destinations in the long term.