Floods have become increasingly frequent and severe in recent years, posing a significant threat to communities, infrastructure, and the environment. Understanding the contributing factors to flood vulnerability is crucial for effective flood risk assessment. While the flood vulnerability indices (FVI) are widely used for risk assessment, they typically consider only common variables such as physical, social, and economic factors. This study is significant as it addresses the gap in understanding how additional variables influence flood vulnerability, particularly in recent years, as the world experiences increasingly unpredictable climate patterns. Hence, the objective of this study is to identify the factors influencing flood vulnerability using Kuantan River Basin (KRB), as the study area. Semi-structured interviews were conducted with professionals in hydrology, urban planning, environmental management, and socio-economic development. The interview data were then analysed using thematic analysis. The thematic analysis identified four key categories of significant variables: (1) hydrological, (2) environmental, (3) socio-economic, and (4) climate change effects. These findings highlight that, in addition to the common variables, climate change also plays a crucial role in influencing flood vulnerability. The findings further reveal that climate change and flood risks are closely tied, which exacerbates problems with water management. Historical development, water systems, natural geography, and social and economic circumstances all have an impact on community resilience, and the findings advise local governments to apply a thorough policy framework involving urban planning, building limitations, drainage system upgrades, financial policies, and robust mitigating structures to lower flood risk.