Paramedics were called to assist the 57-year-old woman who was bitten by a shark about 200km - or 10 hours - offshore - from Mackay on Wednesday afternoon.
The woman was on a private boat in the middle of the ocean and had been snorkelling on the reef when she was attacked.
She suffered two 30cm lacerations across her calf.
The crew on the boat provided first aid by wrapping a bandage around her calf to stop the bleeding.
"If that first aid hadn't been done appropriately, there could have been a risk of major haemorrhage," Queensland Ambulance Senior Operations Supervisor Shane Tucker told reporters.
"A patient could become quite critical from loss of blood."
Navy vessel HMAS Warramunga was tasked with retrieving the woman as she did not need to be airlifted thanks to the first aid she received from her boat's crew.
Mr Tucker said it would have been a difficult retrieval without the navy being able to assist.
The navy arrived at the boat about five hours after the triple zero call to provide medical assistance and take the woman to Mackay Harbour.
Mr Tucker said the woman remained alert throughout the ordeal but was in pain and shock.
Paramedics took over when she arrived at 12.45am on Thursday and transported the woman to Mackay Base Hospital in a stable condition where she would receive stitches.
It remains unclear what type of shark was responsible for the attack.