Anthony Larose (30) and Kieran Larose both died instantaneously of head injuries when they plunged 25 metres into the opening of a cave at the base of the Pinnacle Rock on 31 July.
In a statement read to the court, Mr Larose's wife, Sheila, described how she had handed their infant son to his father moments before he lost his footing.
Mr Larose, a climbing instructor in the army, had taken other children to look into the cave when Kieran asked what his Daddy was doing and was taken to have a look.
Before the fall, some of the children had climbed the Pinnacle Rock, which is between Grosnez and Plémont on the north coast, with Mr Larose, but without the ropes and other equipment that he had taken with him.
Det con Sarah Hamon, the chief investigating officer, said that there were no suspicious circumstances surrounding the deaths.