Aim To evaluate the suitability of marine lactic acid bacteria (LAB) as starter cultures for Sargassum sp. fermentation to enhance its antioxidant and anticoagulation activity. Methods and Results LAB isolated from marine source were characterized for their ability to utilize seaweed as a sole carbon source and applied to Sargassum fermentation. Fermentation period was optimized by monitoring the fermented sample at regular interval for a period of 18 days. Results revealed that a fermentation period of 12 days was effective with maximum culture viability and other desirable characteristics such as pH, total titratable acidity, total and reducing sugars. Under optimum fermentation period, the sample fermented with P1-2CB-w1 (Enterococcus faecium) exhibited maximum anticoagulation activity and antioxidant activity. Conclusions The study reveals a novel well-defined starter culture from marine origin intended for seaweed fermentation for recovery of bioactive molecules. Significance and Impact of the study The study provides information for the enhancement of bioactive molecules in an eco-friendly manner and also paves a way towards the development of wide range of seaweed functional foods.