Mulenga is set to join the Buccaneers on a three-year deal from 2016 Zambian champions Zanaco, said the club.
The 28-year-old netted three times for Chipolopolo at the recent CHAN tournament in Morocco, before the nation was eliminated at the quarter-final stages.
“We are delighted to have finally secured the services of Augustine. He is an accomplished player who has all the qualities to make an immediate impact at the club," said Pirates' administrative officer Floyd Mbele in a statement.
“I would like to thank Zanaco management for their professionalism during negotiations.”
Mulenga is expected to arrive in South Africa early next week.