The research works underpins the link of future climate changes and its impacts on rice crop productivity over, among others, the Mekong Delta in Southern Vietnam. The study applied climate outputs of a high spatial resolution regional climate model (WRF) as inputs to the DSSAT crop modelling system. These dynamically downscaled WRF outputs from three different global models (CCSM3, MIROC-medres and ECHAM5) were used to analyse crop growth under a wider range of climate uncertainties. The findings from this study suggest that rainfed crops, as expected, produce less yield than irrigated crops. Significant rice production reduction of about 35% is projected in the period of 2020-2050 period due to decreases in future rainfall amounts. Though irrigation could significantly improve crop yields, the main challenge is to find water sources given decreases in rainfall. With 90% of rice export from Vietnam originating from the Mekong delta region and given Singapore’s total rice import from Vietnam being about 30%, the study findings that rice yield is expected to reduce by 35% in 2020-2050 is crucial. This information is useful for Singapore’s policy makers in their strategic planning to tackle rice supply and price increase in the context of Food Security. The study is also useful to insurance agencies and other regional stake holders. This study will be extended to cover rice areas over Thailand and also over India along with inclusion of other staple crops and vegetables.