Excitement is mounting as the crowd brave the chilly 11 degree temperatures to await Donaldson 's arrival.
Donaldson, 48, left Coffs Harbor in Sydney two months ago on May 2, and has been paddling for up to 20 hours a day.
Sarah said her husband hadn't been on dry land since May 18 - when he landed on Lord Howe Island - and he is particularly craving a steak-and-vegetable pie.
She and Zac are still inside. There is no wind or rain. It is understood Donaldson is just outside the harbour entrance and due to come ashore with the next 20 minutes.
Donaldson is attempting to raise funds for asthma research, a disease both he and his young son suffer from.
This was Donaldson's second attempt at the crossing, with his first attempt in 2014 thwarted just under 80km out from the endpoint when he lost his rudder and was unable to recharge his radio batteries.
These issues, combined with head and chest injuries he received in a particularly rough night at sea, caused him to be winched to safety from the water, abandoning the attempt.
Now, four years later, he is close to fulfilling the journey across the Tasman.
Donaldson's crossing this time hasn't been without incident either, with stormy weather and shark issues making for some nail biting moments.
Donaldson and his wife have stayed in contact via a satellite phone during his crossing and in one conversation they had in late May, he told her about his encounter with a large shark.
He said the shark, about 2.5m in length, chased him, trying to bite the kayak's rudder.
A couple of weeks later, in mid-June, a lightning storm also caused concern for the team.
Donaldson said a fierce lightning storm hit the area he was navigating through.
With both the kayak and the paddle made of carbon fibre, this left Donaldson anxious until the storm passed as carbon fibre is an excellent conductor of electricity.
He therefore had to sit the storm out to avoid moving his paddle through the air while the storm raged around him.