With an estimated 10,000 craft on the water, it is the busiest day of the year. And it happens every year on the last Monday in January as Aucklanders take to the water to celebrate their Anniversary Day.
With the highest boat ownership ratio in the world, it is appropriate that the occasion focuses on the harbour.
The weather always seems to co-operate and it is a time for sunscreen, hats, picnics - and fishing.
While snapper fishing in Auckland is usually centred on the channels, including the Motuihe, Sargents and Rangitoto, throughout summer it is not necessary to use more than a cupful of fuel travelling from the launching ramp or marina to the fishing spot. The snapper move into the inner harbour in large numbers before Christmas and remain until cooling water temperatures trigger a migration to deep water in the outer Hauraki Gulf.
At 21C, it is three degrees cooler than last year but it is enough to bring the fish in close, and on Monday the racing yachts and spectator craft dodged fishing boats anchored off the naval dockyard, Stanley Point, Bayswater, the Tank Farm, the ferry terminal and the marine rescue centre.
Parts of the harbour are designated shipping channels and anchoring a boat is not permitted, but many of the anglers are fishing with lures like soft plastics and are drifting.
The charter vessels which operate out of Z Pier in Westhaven do not have to motor for more than a couple of hundred metres before dropping the anchor right off the Tank Farm, and they catch the quota of snapper for their customers without moving. And they often catch bigger fish there than they do out in the Motuihe Channel.
Like all snapper fishing, the key to catching fish in the harbour is to work the tides and change with the conditions. At slack tide a flasher rig or ledger rig will catch fish, but as the current starts to run it is a better option to switch to a long trace below a sinker.
A triangular sinker of about four ounces will sit hard on the bottom rather than roll along like a ball sinker.
And as the current picks up a longer trace or about 2m will produce better than a short one.
It is common to have two hooks on a long trace, often with one a sliding keeper hook and both hooks are buried in a strip of bait; but in the harbour you will catch more fish with two fixed hooks about 10cm apart, and recurved hooks like those used on a ledger rig will hook more fish than the octopus hooks usually put on the end of a trace.
One party fishing on a charter boat last Wednesday filled their quota with this approach and the best bait was small chunks of mullet.
Big baits are a handicap in this situation and as one skipper says: "You want to make it easy for the snapper to swallow the bait.
"One small mouthful will work much better than a large bait they can chew on without getting hooked. In fact you will catch more fish by leaving the rod in the rod holder and letting them hook themselves.
"Just wait for the rod to bend.
"If you lift the rod and try to strike the fish every time you get a bite, you are just pulling the bait away from them."
Another trick is to put a bait on each hook, rather than rigging both hooks in a single bait.
That makes sense. If one bait is stripped off, there is still another one working for you.
As well as mullet, other baits like kahawai, trevally and mackerel all work well, and the trick is to use fish which have been frozen. It breaks down the flesh and makes it more juicy but still tough enough to stay on the hook.
The popular baits like squid and pilchards will also catch fish. It's more a question of presenting the baits hard on the sea bed in a strong current.
This is harbour fishing at its best and there are not many places in the world where in a city of 1.4 million people you can catch a bin of 2kg snapper while classic yachts, ferries, gin palaces and a host of smaller craft stream past.
