The diet includes other sharks, skates and rays, many kinds of large bony fish, and invertebrates including squid, crabs, sea cucumbers and shrimp. This shark has also been known to scavenge on dead animals such as seals, whales, and bait from long-lines set by fishermen.

The bluntnose sixgill is a capable hunter as well as a scavenger. It consumes a wide variety of bony fishes including sharks, skates, rays, chimaeras, dolphinfish, small swordfish and marlins, herring, grenadiers, antimoras (codlings), rockfishes, cod, lingcod, hake, flounders, halibut, turbot, gurnards and anglerfish.

The diet of bluntnose sixgill sharks can vary depending on their life stage. Juvenile sharks tend to feed on smaller prey items such as squid and small fish, while adult sharks prefer larger prey items such as dogfish and other sharks.

They are a generalist species that feed nocturnally on a variety of food based upon its availability, such as fish, rays, squid, seals and other shark. They ambush prey and are able to prodtrude their jaws and tear food with 6 rows of saw-like teeth.

These sharks are highly skilled predators whose diet consists of fishes, rays, crustaceans, sharks, and even carrion. While not very fast, it is thought to ambush prey at close range with a quick strike. Whatever it cannot swallow whole it will grind up in the rows of sharp teeth.