The bio-accumulation of heavy metals in macroalgae poses significant risks to marine ecosystems and human health. In this study, heavy metal distributions of macroalgae and potential health risk assessment in the Mersin inner Bay were determined from macroalgae (Stypopodium schimperi, Padina pavonica, Laurencia obtusa, Dictyota sp., Sargassum vulgare, Jania rubens, Halopithys sp., Osmundea sp., Halopithys incurve, Ulva intestinalis, Entromorpha flexuosa, Ulva linza) samples collected between February and September 2021. The levels of heavy metals were found as 1.24-5.93 g/kg for aluminum, 0.61-5.26 g/kg for iron, 1.17-7.61 mg/kg for cobalt, 0.03-0.21 mg/kg for cadmium, 4.26-43.10 mg/kg for chromium, 0.28-437.52 mg/kg for cupper, 17.90-139.08 mg/kg for manganese, 2.78-79.25 mg/kg for nickel, 0.75-3.49 mg/kg for lead and 1.71-70.34 mg/kg for zinc, respectively. The potential risk assessment of macroalgal species using the calculated total cancer risk (TCR) suggested high carcinogenic risk from the carcinogenic chromium, copper and nickel (TCR>1.00E-04).