The incredible creatures were spotted by fishermen in recent days and finally captured on camera.
Marine biologists estimate that there are up to nine Orcas and all belong to the same family or pod.
Local wildlife ranger Emmett Johnston captured images of the whales off Dunree Head on the Inishowen Peninsula.
Mr Johnston told Donegaldaily.com he has been waiting seven years for the moment since first seeing a grainy picture of a lone Killer Whale back in 2005.
“There are occasional reports of them around the coastline but never on this scale.
“We think there was up to nine of them together and that is extremely rare.
“It was just amazing to watch them. The most amazing thing was that they were so close to land,” he said.
The whales, which have a distinctive white marking on their side, feed on mackerel and also seals.
Emmett said himself and his colleagues suspect the whales are a group which spend a lot of time off the Outer Hebrides in Scotland.
He said the sighting of the rare whales, the largest of which he estimates was 30 feet long, is proof that Ireland’s waters are awash with such life.
“What it shows is the potential for people to go out and see such amazing creatures literally on their doorstep.
“Before this the closest I would have seen these creatures was on the Discovery Channel on television.
“But just 20 minutes in a boat and I was beside them on a boat watching them in all their beauty,” he said.
Emmett added that although there is no recorded incident of Killer Whales attacking people, he would urge caution around them.
“If people are thinking of going out to see them then I would ask them to exercise caution.
“If they turn off their engine and look at the whales from a distance, there is a good chance the whales will come and take a look at them,” he said.
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