Sandworms eat seaweed and microorganisms. Sandworms are known to be omnivores. Their diet consists of surface sediment, plant and animal remains, aquatic organisms, including small crustaceans, mollusks, and other worms . They are oftentimes exposed to metals through their diet and their burrowing tactics.

Sandworms hide in their tunnels and dart their heads out when prey wanders within striking distance. They use their thick, hook-like teeth to grab their prey, which they then drag back inside their tunnels.