The diver, in his 40s, was injured in the suspected attack about 11.20am local time (1.20pm AEST).
It took place about 300m-500m offshore at Quondong Beach, north of Willie Creek.
The diver was taken to Cable Beach for treatment.
He was conscious and breathing.
The Department of Primary Industries and Regional Development (DPIRD) is currently investigating.
It’s believed the animal involved was a three-metre tiger shark.
A witness told 6PR radio that the victim had seemed “pretty chill”.
“There was probably every cop in Broome just racing down the beach with the lifeguards,” he said.
“It was all pretty cool, calm and collected really. They just got him in the ambulance and drove off.”
People have been urged to take extra caution in the Quondong Beach area.
Charles Cernobori, 59, had been bodyboarding 30 metres off the iconic tourist beach when he was attacked and suffered fatal injuries.