The vibe tended a little to the shambolic. Most people had dressed up, a bit, but the heat and the proximity of the beach stopped all that from going too far. A proper shirt, a decent sunfrock. In the inner circle the men were all in suits but in the cheap seats up the back more than one kaumatua wandered around in bare feet. Sharon Hawke, from Ngāti Whātua, wore shorts and sunglasses, inside.
It was very hot. Outside, across the deck and through the pōhutukawa, the sea sat quietly, waiting for them. Who wasn't looking forward to a swim?
But first, the meeting. What do you do, second time round, when last time it genuinely was momentous? Mark the progress you've made is the best answer, but fixing the social and economic ills that affect Māori is not a thing you can do in a year.
The Iwi Chairs had set a high symbolic tone, giving the PM a pendant in the shape of a toki, or adze, made from 40,000-year-old kauri. They called it Te Aroha.
"I know who this is for," said Ardern. "And I will keep it safe for her." The PM's daughter's middle name, for those visiting the dark side of the moon last year, is Te Aroha.
They set about inspiring each other, saying the things they said needed to be said, listening with all their hearts, committing to the dialogue, proclaiming the value of the kōrero. Each side was up for it: strutting, in the nicest and most open and honest way, its skill with high-blown rhetoric and jokes; subtle, pointed allusions and revelations that reveal just so much and not too much. Marae debate. Government parley-time.
The Waitaha Room is a sort of cultural no-people's-land. It's got the shape and size, even the rafters, of a wharenui on the marae, but it's not a wharenui, it's a meeting hall. They had a fierce and formal powhiri in the only place they could have it: the carpark.
And in the end, rhetoric and goodwill aside, not a lot was said. The iwi chairs had met the day before and drawn up their list of items to present, but it was very top line. The Prime Minister and her colleagues responded with due earnestness. Then they stopped and had lunch.
Still, there were some markers. The Government and the forum are back to talking to each other about water rights, though still far from agreement. That might be significant.
Iwi have said they could build 270 new homes by 2020, provided reasonable funding mechanisms are put in place. That doesn't sound like a lot, but it could be the unlocking of something much bigger. Minister for Māori Development Nanaia Mahuta said, pointedly, the last time there was a significant upswing in Māori home ownership was in the days when you could capitalise the family benefit - which we no longer have.
Then she talked about the potential for using iwi assets in a similar way, and the PM later made the same point. Watch that space.
Last year, Ardern became the first woman prime minister granted the right to speak from the porch of the whare runanga on the treaty grounds. She used the moment to call the relationship between Māori and Pākehā the great defining project of this nation.
"I believe in the power to change," she said then. "We as a Government know the failings, but we won't always know how to change. We will come to you, to ask. No marae will be too small. And I ask you now, to ask us what we have done. You must hold us to account."
The iwi chairs did not hold her to account. Re-establishing their place at each other's tables was the task of the day.
But the process is underway and there are many more days to go. Yesterday, Ardern said: "We increasingly want to use Waitangi as a place and time for dialogue." As she did last year, she'll be mixing marae visits with treaty-ground engagements, and she's not going to pass up the chance to serve breakfast to the masses, after the dawn ceremony on Waitangi Day itself.
The apron and barbecue tongs of 2018 still mark the supreme populist moment of her prime ministership. This year, though, it may not be the biggest thing that happens.
That's because on Monday there will be true glory. Sir Hekenukumai Busby, the great pioneer of the waka renaissance, now 85, will formally be invested with his knighthood, right there on the Waitangi Treaty Grounds. I'm expecting an occasion for the ages.