<p>One of the main issues impacting marine life and human well-being is the contamination of marine ecosystems. This study aims to monitor heavy metal accumulation along the Thikkodi Sea coast of Kerala, Southwest India, using macroalgae as a bioindicator. We examined heavy metal concentrations in five macroalgae species (<i>Ulva</i> sp., <i>Caulerpa</i> sp., <i>Dictyota</i> sp., <i>Sargassum</i> sp., and <i>Gracilaria</i> sp.) collected from intertidal regions in the post-monsoon season, along with seawater and sediment, using Energy Dispersive X-ray Fluorescence (EDXRF) analysis. Among the metals studied, Iron (Fe), Nickel (Ni), Copper (Cu), and Chromium (Cr) showed the highest accumulation in the algal species <i>Sargassum tenerrimum</i>. <i>Gracilaria corticata</i> exhibited elevated levels of Manganese (Mn), while <i>Caulerpa sertularioides</i> contained significant amounts of Zinc (Zn). Statistical tools, such as one-way ANOVA and correlation analysis, supported the significance of these data. The brown algae studied displayed the highest Bioaccumulation Factor (BAF) values, indicating their remarkable ability to absorb heavy metals from the surrounding water. The BSAF values of the brown algae <i>S. tenerrimum</i> and <i>Dictyota ciliolata</i> suggested the potential for hyperaccumulation of heavy metals, such as Copper (Cu) and Cadmium (Cd). These properties make seaweeds important bioindicators of pollution. Promoting seaweeds as biomonitoring tools can aid in implementing sustainable monitoring procedures and accurately tracking marine pollution.</p>