James Kane and Barbie Agostini threw a rope with a magnet attached to the end into the lake in Meadows Corona Park in the Queens neighborhood.
They opened the safe and found it filled with damaged $100 bills.
They said police told them the money was not linked to any crime and they allowed them to keep it.
Kane said, "We've found safes many times before. I saw the money and I said this is not possible," Kane said.
Agostini noted that they could not find any identification to identify who the safe belonged to.
Magnet fishing involves throwing a line with a powerful magnet attached to the end into lakes and rivers.
The duo said they started as a hobby during the COVID era and had previously found grenades from the Second World War, 19th-century weapons and a motorcycle.
