Climate change is a global issue that significantly impacts various regions, including South Asia, which is particularly vulnerable to climate extremes. Extensive research is required to address the complex interplay between climate change and extreme weather events in South Asia (Bangladesh, Nepal and Pakistan). This study presents a case study of an Asia-Pacific Network for Global Change Research (APN) project focusing on climate change research, capacity building and science-to-policy communication on climate extremes in South Asia. Climate change research emphasises the importance of research to understand the changing patterns and impacts of climate extremes in the region. It underscores the need for robust scientific methodologies, data collection and analysis to generate reliable evidence for policymakers and stakeholders. The capacity building efforts involve training programmes, workshops and knowledge-sharing platforms, which are critical to enhancing the capabilities of local researchers, institutions and communities in conducting climate change research and developing adaptation and mitigation strategies. The science communication includes disseminating the study’s findings to stakeholders, including policymakers, researchers, communities, media and civil society organisations. Overall, collaborative efforts between South Asian countries are important for climate change research, capacity building and science-to-policy communication to build resilience and mitigate the impacts of climate change.