Vic fishing trip turns tragic

A man has died after falling overboard into freezing waters during an early morning fishing trip in a Victorian waterway.

Koo Wee Rup man Ian McBride, 53, and his fishing friend Colin Maddern of 40 years set out from Tooradin to Western Port Bay on Saturday night but only one came home.

Mr McBride fell overboard and drowned despite the efforts of his friend who jumped into the water after him.

Mr Maddern was rescued by a passing boat after spending two hours floating in the dark at 3.20am on Sunday.

"He was treated for hypothermia after he had been in the water for around two hours," an Ambulance Victoria spokeswoman told AAP.

Police are investigating the circumstances leading up to the man's death and will prepare a report for the coroner.