The devices were found during a routine patrol by a local coastguard rescue team.
But the find has not surprised residents of Nairn, Highlands, as the devices were used to train British troops in the run-up to the D-Day landings in Normandy, France, in 1944.
Photographs of the devices - four solid shots and a barrage rocket with its warhead still intact - were sent to the Royal Navy’s bomb disposal unit at Faslane naval base.
Ordnance experts then travelled to Nairn to make the area safe.
Petty officer diver Adrian Wilcock said: “There was little risk to the local population.
“Obviously, if you were to go up and start messing about with a piece of ordnance there is the chance of a possible initiation but it’s been rolling around on the seabed since WWII and it’s very unlikely it would have initiated, but you can never say never.
“Everything has been expended. It was nothing out of the ordinary.”
Bill Shand, 91, from Nairn, a former naval seaman who survived the Arctic Convoys before joining the crews bound for Normandy was not surprised by the find.
He said: “I’m not surprised by this find really, when you consider the events of the time.
“People here appreciated that Nairn provided an ideal training ground to give our troops an idea of what they’d be up against.”
John McInnes, 83, recalled how as a young boy he saw the military training for the landings on the beach.
He said: “They used flares on parachutes. You sometimes used to find the empty cases.
“We used to go along and watch what was happening. They were building the ramps for tanks to come ashore and the soldiers used to offer us cups of tea.
“I’m not surprised we’re still finding these things. The beach used to be littered with men on the exercises.”