This paper investigates the livelihood vulnerability experienced by agricultural households in Kuttanad, a below sea level farming system in southern India, in the aftermath of a major flood in August 2018. For this purpose, we constructed a flood coping strategy index (FCSI), to measure coping strategy intensity, using the data on the severity and frequency of various coping strategies adopted by households. Furthermore, we estimated a Tobit regression model to identify the factors influencing the intensity of coping strategy choices. The FCSI revealed that only two per cent of agricultural households experienced a ‘severe’ level of vulnerability because of the quick and effective policy response of the Kerala state government. In addition, Tobit regression analysis indicated that female‐headed and labour households are more vulnerable than their respective counterparts. While income exerts a negative influence on the degree of livelihood vulnerability, agricultural landholding has a positive effect, as it increases cultivation loss during a flood.