"This is the nearest I'll ever get to see Charles because in London the security is so massive," he said.
Youngsters complete with pirate hats had been out for a sail on The Spirit of New Zealand in the morning and waited patiently on board for Charles to arrive.
Charles and Camilla spent some time in Auckland on Sunday, where members of the public turned out to greet them in the sun-drenched Aotea Square before they met with several charities.
The royals will wrap up their seven-day tour of New Zealand when they leave from the Whenuapai Air Force Base about 10.30am.
Live Update:
10:25: Prince Charles has boarded the boat and is shaking hands with the captain and crew.
Some of the young people on board - trainees on the Spirit of Adventure - are chatting with the prince as he makes his way on board.
Bystanders Ellen and Ann Cockburn, from the UK, said it was just a happy coincidence they were on the wharf at the right time.
"I'm from Wales and he's the prince of Wales, so it fits," Ellen Cockburn said.
"It's a happy coincidence that he's sharing the same time in New Zealand with us. I'm perfectly prepared to smile at him."
Charles is having a chat with Spirit of Adventure staff as he makes his way to the bow of the boat.
After a quick wave goodbye Charles has left the ship and is walking along the row of fans, shaking hands and chatting.
10:39: The prince and his entourage has now left the wharf, on his way to Whenuapai.
Mr Field shared a quick joke with the prince, as he left the wharf.
"I shook hands with Charlie and as a bit of humor I said I would see him back in the UK. He said how long have you been here, I said 15 years and he said 'You won't like it'.
"He couldn't be more relaxed hes a fantastic ambassador. He's welcome everywhere."
The Spirit of New Zealand vessel has now set sail again.
