We analyzed the distribution and bioaccumulation of six heavy metals (Cu, Pb, Zn, Cr, Cd and Hg) in marine organisms, water, and sediments from China's Hainan and Zhoushan coastal regions. In all marine organism, seawater, and sediment samples, Zn and Hg had the highest and lowest concentrations, respectively. Heavy metals in marine organisms varied by region and species, with concentrations being higher in Zhoushan than in Hainan (except for Zn) and in crab than in fish. Marine organisms' ability to digest and eliminate heavy metals (bioaccumulation ability), based on bioaccumulation factors, was significantly higher for heavy metals in seawater than in sediment. Higher sediment background values may explain the higher heavy metal concentrations in crab. Generally, marine organisms' bioaccumulation ability was higher for Cu and Zn and lower for Pb. Findings specific to the coastal environments may be generalizable to other coastal areas in China or worldwide.