Bacteria associated with marine macroalgae like Sargassum wightii and Halimeda macroloba play key roles in promoting host growth, producing bioactive compounds, and enhancing stress tolerance, making them promising candidates for use as microbial biofertilizers. The study focuses on the isolation and characterization of bacterial strains from the holdfast region of Sargassum wightii and rhizoidal region of Halimeda macroloba, collected from the coastal area of Thonithurai in the Mandapam region of Rameswaram, Tamil Nadu. The isolates were initially characterized using morphological traits, Gram staining, and biochemical assays. Two strains from Sargassum wightii showing notable biochemical characteristics were selected for species level identification through 16S rRNA gene sequencing and BLAST analysis. Bacillus subtilis (isolate IB.6a.1) exhibited 95% sequence similarity with reference strains. Halobacillus dabanensis showed 97.8-99.4% similarity with other Halobacillus species, and phylogenetic analysis further confirmed the classification of both isolates within their respective genera.