Shark Experience, a shark-diving operation in Bluff, led the hunt for the shark tag, which had come loose from a great white shark being monitored in Australia in recent weeks.
About 4.30pm yesterday, shark tag searcher Kelsi Hayes and her canine companion Quasi found the small shark tag.
Quasi the dog was the first to sniff out the tag, finding it tangled up in a pile of seaweed.
Shark Experience crew member Nikki Lad said they had been notified by a research team in New South Wales that a tag on a great white shark had come off.
The tag had been traced to a beach near Fortrose in Southland.
Information they had received yesterday was the tag was on a surface where the temperature was fluctuating from hot to cold, suggesting it was on a beach, Ms Lad said.
Shark Experience wrangled as many helpers as it could and went out to search during a one-hour window yesterday afternoon when the tide was low enough to get on to the beach.
Ms Lad said the beach was spectacular, but most of the time was underwater. The beach was also covered with hundreds of black mussel shells which increased the challenge of finding the tag.
Ms Lad said they located the shark tag on the said beach, in the said place, sitting in seaweed.
"It was exactly where they said it would be."
Great white sharks travelled from Australian waters to waters around Southland and Stewart Island at this time of year. Many of the sharks found around Southland waters this year were males getting ready to start building their hierarchy ahead of the breeding season, she said.
The research was vital as it helped develop information on the waters the animals covered and their range.
The tag would go back to the Australian team, who would analyse the data, which would show where the shark had been in the past few months.