Indian Sundarbans, a part of the largest delta on planet Earth, is one of the most stressed regions in the world from crop production point of view. Dry season crop production is limited by the non-availability of suitable irrigation water, which can only be supplied from surface water resources. The present research aimed at assessing the dynamics of surface water resources acreage during the dry (post-monsoon and pre-monsoon) seasons of 2017–18, 2018–19, and 2019–2020 cropping years in the Gosaba CD block of Indian Sundarbans. Normalized Difference Water Index (NDWI) computed using multi-temporal Sentinel-2 data was used to estimate the changes in the surface water area during the entire dry seasons. Binary classification of NDWI images was used to separate water bodies from the non-water classes. The results revealed that the surface water resource area was higher just after the monsoon (end of October). About 2.83, 1.63, and 3.74% area of the block was estimated as surface water at the end of monsoon season of 2017–18, 2018–19, and 2019–2020 cropping year, respectively. Surface water area notably decreased in December. Higher acreage of surface water in February might be attributed to the presence of standing water in the transplanted boro rice field. As the season progressed, the areas under surface water resources decreased and became lowest in March. Intensity and distribution of rainfall influenced the availability of surface water resources. The findings of the present study may contribute to sustainable crop planning in the Indian Sundarbans region.