In order to understand how nature can be leveraged for sustainable policymaking, Thailand is among the first Southeast Asian countries to undertake the National Ecosystem Assessment (NEA), alongside Cambodia and Viet Nam. The NEA Initiative, led by UNEP-WCMC and working in collaboration with UNESCO and UNDP, has supported 14 countries in conducting assessments on biodiversity and ecosystem services and their interlinkages to people. The Assessment harnesses multistakeholder engagement, linking science, policy and practice. Thailand is focusing its Assessment on marine and coastal ecosystems, paying special attention to the role of Indigenous and local knowledge.