Sedimentological and heavy mineral studies were carried out for two offshore profiles in the Kalbadevi Bay, Ratnagiri, Maharashtra. The surface samples from the Bay were collected during pre- and post- monsoon period (i.e. in May and October respectively) and studied to find out effect of south-west monsoon on the distribution. It is observed that greater than 95 % of the sediments comprises of sand and comparatively, post-monsoon (October) sand content is higher than that in pre-monsoon (May) and transitional period (January). Fine sand (0.125 mm) contains abundant magnetites during pre- and post- monsoon period. Ilmenite shows slight increase in concentrations from fine sand to very fine sand (0.0625 mm) from pre- to post-monsoon period. The magnetite concentration along both profiles varied from 0 to 44 % during January and May (Pre-monsoon), and increased from 3 to 91 % during October (post-monsoon). Ilmenite concentrations showed mixed behavior, which varied from 0 to 100 % in January, 52 to 100 % in May, and 8 to 96 % in October. The data obtained is useful to decide the operations of offshore placer mining system in the Kalbadevi Bay.