Deltas are highly sensitive to erosion, flooding, and salinization with consequential agricultural productivity losses and out-migration, which is a preferred adaptive measure for the inhabitants of deltaic islands. This study investigates the associations between agricultural productivity decrease, household poverty and the probability of out-migration in the Indian Sundarban Delta (ISD). Using newly collected survey data from randomly selected households within the ISD, we analysed these relationships by means of descriptive statistics and regression modeling. Results suggest the significant positive association between a decrease in agricultural productivity and out-migration. The results further show that ceteris paribus, out-migration is negatively associated with household poverty, which is likely to be explained by the effect of remittances. The results yield important policy implications at the local level and can contribute to the progress towards sustainable livelihoods in these deltaic islands.