Fuller had already caught his fill of scallops and was back in the boat when they arrived, quickly whipping out his phone and filming the experience.
"They started playing around the boat, pushing it from side to side and playing with the anchor chain," Hulston continued.
"I'd be lying if I said I wasn't a bit scared, I've seen what they do on Animal Planet ... If Mark didn't get the footage, no one would have believed me."
The pair had been diving in Hooks Bay (northwest Waiheke Island) when the four orcas paid them a visit, two small and two bigger ones.
Footage from Fuller's phone showed orcas swimming around the boat and one coming within metres of Hulston as he clambered out of the water.
However, while he was still in the water the apprentice builder curiously peeked underneath the boat.
"There was one less than two metres away just turning sideways," he said, "It gave me a cheeky grin and its teeth were literally the size of steak knives."
After the left Hooks Bay, the pair saw the orcas once more around the corner in Garden Cove, again coming over to the boat to investigate.
Both of the divers had spotted orcas in the deep blue before, however, never had they experienced anything like that day's encounter.
They were surprised at the orcas' curiosity, swimming up to the boat and playing in the water around them.
A builder from Whangārei, Carter said he had been fishing since he was a teenager and it was his first close-up encounter with such a massive animal.
However, when he first spotted the whale he thought it was a windsurfer having trouble getting his sail out of the water, as it kept hitting the water.
Using binoculars they established the whale was swimming on its side with its fin dropping and slapping the water.