The present study was designed to screen the biological activities of marine micro algal samples collected along the South Indian coastal belt. For that the marine water samples were collected from different coastal locations such as Colachel, Kadiapattinam and Muttom of Kanyakumari District, South India. The collected sea water sample were filtered, serially diluted, supplemented with Walne's medium and subjected to light incubation under laboratory conditions for two weeks for optimum growth and the algal species were identified and isolated based on their morphological characteristics with the help of light microscope. Totally 10 isolates, 5 from Muttom seawater collection, 3 from Kadiapattinam and 2 from Colachel collections were identified. 5 isolates from the Muttom seawater collection was evaluated further. In this evaluation, the growth pattern of isolated algal species was studied and their mass production was done. The cultured algal species were subjected to centrifugal separation and solvent extraction by using three solvents such as ethyl acetate, methanol and water. The supernatants collected were evaluated for the antimicrobial activity against three fungal pathogens viz., Aspergillus niger, Candida albicans and Mucur sp. In the antimicrobial evaluation, the methanol extract of S–2, S–3, S–4 and S–5 samples showed a significant antimicrobial activity against the tested fungal culture. Our further studies directed toward the identification algal species, phytochemical screening and various detailed pharmacological screening may give more valuable results.