The mantas swept past in formation, one after another.
Great dark shapes as wide as a car is long circled once then twice, then three times.
Four males, one jet-black, were all courting a female.
For a moment the divers caught a glimpse straight into their impossibly big mouths.
Then they dipped down, missing hanging legs by centimetres, before banking sharply and coming back for another go.
Right off the beach where the 200 metre seawalls would cut through the dunes and out into the lagoon where hundreds of boats would spill and pollution flow, five divers tried to muffle their excited exclamations as an equal number of enormous manta rays circled them.
Despite their efforts, a few snorkel-squeals and snorts escaped. For two of the divers, Toni Collette and David Galafassi, this was the first time.
To be in the water with such big animals, to immerse oneself into their world even for a few minutes, is profound and humbling, and indescribably exciting. No one forgets their first dive with the manta rays of Ningaloo.
Toni Collette heard about the Ningaloo Reef and the threats it faces from fellow Aussie, author Tim Winton.
Upon arrival back in Australia a few months before, and exhausted after a relentless filming schedule, Toni was catching up on her mail when she came across a letter from Tim and an information package from the Save Ningaloo campaign.
After looking at the materials and seeing the plans for a massive marina resort, Toni decided that this was an issue she just had to act on, as have tens of thousands of people before her in Australia and around the world.
Toni was so captivated by the descriptions of Ningaloo's wildlife, and astonished by the threats posed to it by inappropriate development, that she picked up the phone and contacted the campaign immediately, asking how she could help.
A few months later, after filming in the 'outback' of WA for a film called "Japanese Story," Toni was in the water experiencing for herself the magic that is Ningaloo.
Toni and David spent time hearing about the cycles of wildlife at Ningaloo, and the importance of Batemans Bay. They also snorkelled over coral gardens, saw endangered turtles and hundreds of fish.
They heard about the plans to build the giant resort, walked across the natural sweep of beach where it would go, and learned about concerns held by scientists who are just beginning to understanding the complex ecosystems of the lagoon.