Trichodesmium plays a critical role in nitrogen fixation and primary production in marine ecosystems. Understanding its light absorption properties is essential for advancing remote sensing techniques to monitor its distribution and ecological impact. This study focuses on the spectral signatures of Trichodesmium erythraeum and T. thiebautii, observed in bloom conditions in the coastal and open ocean waters of Arabian Sea. Both species exhibit distinct absorption peaks associated with chlorophyll-a and phycobiliproteins (phycocyanin and phycoerythrin). Key spectral features include pronounced peaks around 437 nm and 678 nm for chlorophyll-a, and additional peaks near 494, 546, and 627 nm, attributed to phycourobilin, phycoerythrobilin, and phycocyanin, respectively. These spectral features enable Trichodesmium to efficiently capture light across a broad spectrum, enhancing its photosynthetic efficiency in oligotrophic oceanic regions. The results from this study provide critical data for refining remote sensing algorithms, particularly in distinguishing Trichodesmium from other phytoplankton communities.