Wellfleet Police confirmed the shark attack happened just after noon about 300 yards south of the beach.
Wellfleet Police Lt. Michael Hurley tells The Associated Press the victim, identified only as a man in his mid-20s, succumbed to his injuries following the attack.
The man was pronounced dead at Cape Cod Hospital in Hyannis.
#BREAKING: Wellfleet Police confirm they are down at Newcomb Hollow Beach after a reported shark attack. Extent of injuries/specifics not known at this time. #Boston25
— Courtney Spinelli (@CourtSpinelliTV) September 15, 2018
The extent of the victim's injuries are unknown at this time, but a Medflight was canceled.
Officials said the victim was transported to Cape Cod Hospital by ambulance.
The beach has been closed for swimming.
Comment: Another attack (non-fatal) for the region was reported in August: 'Get me out of the water' man yells following first shark attack in years at Cape Cod, Massachusetts
See also: More than 150 great white sharks spotted stalking coast of Cape Cod