This paper addresses the mainstreaming of uncertainty in Disaster Risk Reduction (DRR) and Climate Change Adaptation (CCA) using as a case South and Southeast Asia, a region highly vulnerable to a wide range of natural disasters. Improvements in the implementation of DRR and CCA at the community and regional levels can be realized when the underlying uncertainties are understood and made transparent by all those involved in the science, practice and decision making of natural hazard management. This theme has been explored in a think tank fashion through knowledge elicitation and sharing among experts in the research community as well as practitioners and policy advisers with extensive experience with and insight into DRR and CCA at the regional and/or local levels. The intended result has been the identification of the means by which the capacity to integrate uncertainty can be developed. In this elicitation process, sources of uncertainty associated with the implementation of best practices in DRR and CCA at the regional and local levels. The results of presented are considered by the stakeholders involved to be valuable in expanding capacity to plan and implement more effective DRR and CCA policies and measures particularly at the community level where uncertainty plays a central role for those most vulnerable to current and future climate extreme events, and socio-economic constraints and changes.