The body of a man who went missing during a boating trip in the Snowy Mountains last month has been found.

At 10.30am on Wednesday, a 70-year-old man spotted a body while cruising Lake Eucumbene and contacted police.

The body of a 56-year-old from Emu Plains who went missing on the lake near Adaminaby on October 17 was retrieved a short time later.

The man fell overboard from a fishing boat last month. His son, who was with him at the time, dived in and searched the water for 40 minutes before swimming to shore and walking for five hours to find help.

Emergency services scoured the area for four days afterwards but failed to find him.

Lake Eucumbene is a popular fishing spot in the Snowy Mountains and the man was on holiday from Sydney when he went missing.

His family have now been notified.