Tantalum (Ta) is a rare transition metal widely used in the manufacture of new technologies such as computers, cell phones, solar panels and implants in biomedicine, and their use is continuously increasing. Most non-essential metals are immobilized in the organism through complexation with proteins, but it is not known if new-technology elements (such as Ta) present the same behavior. In aquatic environments, metals tend to concentrate in biota and some can be biomagnified through the trophic chain, even reaching humans. This study aimed to investigate any possible relationship between Ta and proteins. Invertebrates and fishes were collected from coastal marine ecosystems of northern Chile, Patagonia, and South Shetland Islands (Antarctic Peninsula). A direct positive relationship was found between Ta and total proteins throughout the food chain from marine ecosystems of the Patagonia and the Antarctic Peninsula area, revealing that proteins are probably the pathway by which Ta bioaccumulates and biomagnifies in macroinvertebrates and fish of pristine coastal marine environments. Our data suggest that site-specific factors (e.g., water temperature, pH, geography) may be influencing the environmental fate of Ta. Therefore, further studies are needed to understand the biological implications of this metal.