The divers came across the grey nurse shark on a shallow dive and noticed the animal was in distress.
Closer inspection showed there was a plastic band around her neck that was restricting her ability to pull water across her gills.
In other words, she was struggling to breathe.
So the Aussies decided to take the matter and the shark into their own hands.
The men wrestled the female shark into a plastic tube that looks like a sock. They were then able to bring her to the surface just off Sydney, Austtalia, where a vet cut the plastic loose.
Nurse sharks are generally docile and no threat to humans but as one of the divers pointed out, that was no guarantee.
"When you're dealing with a wild animal like this, anything can happen,” Rob Townsend of the SeaLife Sanctuary and Aquarium told 7NewsSydney.
"Their teeth are always on display, and they are very sharp."
The men are all about saving aquatic life but admitted this was “the first time that we've run this kind of operation in the wild."
The plastic left a large cut on the animal so the team administered an antibiotic shot and let the shark go.
They said she swam away and could be back to 100 percent health in as little as a month.
This isn’t the first-time something like this has happened. Remember the fishermen who saved a shark from choking when they pulled part of a moose out of its mouth?