This study aimed to describe the importance of low carbon policies and address strategies to promote community participation in implementing low carbon cities. Hat Yai City Municipality was observed as a case study on policy and participation. Although Hat Yai is an important economic city in Southern Thailand, it is prone to climate change threats and impacts. The study employed a qualitative design. Primary and secondary data were collected from documents, semi-structured interviews, focus group discussions, and participant observations. Thirty-seven key informants comprising 7 policy representatives of Hat Yai City Municipality, 20 stakeholders in low-carbon model communities, 4 private sector members, 2 media workers, 2 NGO members, and 2 civil society representatives were involved. Through content analysis and data triangulation, the results revealed key influencing factors of low carbon city implementation. The results revealed that the success of low carbon cities depends on the three P-S-P factors. The initial letter P refers to policies at the national and local levels. The following letterS refers to stakeholders who should be fostered on networking and cooperation. The final letter P refers to participation, which should be encouraged through context-based promotion of learning, whereas a cooperation network should be expanded to reach all stakeholders in society.