A scuba diver has died after being struck by a speedboat in Port Phillip Bay this afternoon.
The diver, a man in his 20s, was hit by the boat between Frankston and Mornington shortly before 1:00pm.
A passing boat picked up the injured diver and his dive partner and conveyed them to Frankston Pier.
Paramedics performed CPR on the man but he died on the pier.
The second diver, also in his 20s, did not need medical assistance.
Marine Investigation Unit detectives are investigating the divers death and urging anyone who may have witnessed the incident or knows the identity of the driver of the boat involved to contact Crime Stoppers on 1800 333 000.