Vietnam and Bangladesh are countries already impacted by weather-related extreme events. Scientific modelling projections indicate that climate change, and changes to climate variability, will increase risks for both countries in the future. Targeting this challenging contemporary agenda, this paper reflects on the lessons learned from a collaborative research project, funded by the Asia Pacific Network for Global Change Research, which was carried out jointly in the Vietnamese city of Huế and the Bangladeshi city of Satkhira. The focus on secondary cities was intentional as they face unique challenges – a combination of rapid growth and development, adverse climate-related impacts, and in many cases less institutional adaptive capacity than their primary city counterparts. Whilst numerous assessment tool kits already exist, these have typically been developed for rural or natural resource contexts. Therefore, the objective of this action research activity was to develop a flexible suite of participatory assessment tools and methodologies that were refined specifically for the urban context; as well as being easy to use by local practitioners at the city and neighbourhood scales. This paper summarizes the research and stakeholder engagement activity that was carried out before presenting the main findings from each of the case study cities (detailing both climate-related risks and potential adaptation options). This analysis is further extended to include a reflective critique of the assessment process, a comparative analysis of the activity carried out in the two case studies, and the ‘South–South’ learning process that occurred between project partners. Key findings are then distilled to put forward recommendations in support of climate change assessment activity in secondary cities across the Asia-Pacific region.