Suffering engine problems, the boat had drifted and its skipper had let off a flare for authorities.

Among the police who responded were senior constables Glen Young and Nick Leach.

"The wind had got up so there were whitecaps on the water, so finding a couple of divers in the water was pretty hard, like finding a needle in a haystack," Senior Constable Leach said.

"They're dressed in camouflage gear."

The two spear fishermen, 36 and 28, had attempted to swim about five kilometres to reach the shoreline.

To make matters worse, they found themselves circled by a bull shark.

Police eventually found the pair about 4.25pm, and on the weekend reunited with Mr Smith to remember the near-miss months after the dramatic rescue.

"I looked up and saw the red and blue lights and the relief and gratitude I had then," Mr Smith said.

"I thought I need to get on that boat, especially after seeing the shark.

"Had the officers not arrived, the thoughts I was having were either: with it being dusk and the sun going down, potentially a shark attack or probably one of us potentially drowning."

Senior Constable Glen Young said the timing had been crucial.

"They were quite exhausted when they got on the boat," he said.

"I think they only would have had another hour in the water before they maybe would have possibly drowned."