The night of 16/17 May 1943 was clear with a full moon, perfect conditions for the raid. The 19 specially modified Lancasters of 617 Squadron were despatched in three waves from RAF Scampton. Gibson led the first wave of nine aircraft and was the first to attack the Möhne Dam. His mine was released at 00:28 on the morning of 17 May but despite successfully detonating, the weapon failed to breach the dam. After two further abortive attacks by the second and third aircraft in the flight, the dam was finally breached by Squadron Leader H.M Young's Lancaster. Gibson meanwhile accompanied Young on his approach to divert the Anti Aircraft Fire from the dam towers onto himself and to allow his gunners to provide covering fire. Shortly afterwards, Gibson radioed back to England the prearranged code word, indicating that the dam had been breached.
The second wave of five Lancasters flew to the Eder Dam. The first two mines failed to breach it, but shortly before 02:00, it was destroyed by the Lancaster flown by Pilot Officer Les Knight. Of the third wave of five aircraft, two were shot down on the outward journey and the remaining three had great difficulty in finding their targets since heavy mist had gathered. One pilot did manage to locate and attack the Sorpe, but although damaged, the dam was not breached.
Another pilot dropped his mine on what he thought was the Ennepe Dam, without result, while the remaining crew could not identify their targets in the thick mist and returned home.
It was a long night and only eleven of the nineteen Lancasters made it safely back to RAF Scampton.