JJ Wessels and Colin Whitbread jumped on the wave in Belliveau Village and the tidal bore carried the professional surfers to the causeway in Moncton.
The previous record was eight kilometres, which was set in Alaska in 2011, according to the City of Moncton.
The surfers said the tidal bore is even more impressive than they anticipated when they decided to come to New Brunswick.
However, Whitbread said the Petitcodiac River was also quite dangerous.
"There were death rocks three feet away, this is not for amateur people," he said.
"I mean to get involved in this, you have to be in expert shape, and be like a waterman, I mean we've been surfing our whole lives and this was challenging."
Ben Champoux, the director of tourism and culture in Moncton, said the record is a "big coup" for the surfers and the city.
"The fact that we are surfing it is a big deal. The fact that they surfed it for 29 kilometres will put us on the map in the surfing world," he said.
The surfers didn't take anything to chance when it came to setting the record.
The Moncton official said the surfers visited New Brunswick two weeks ago, without any fanfare, and tried surfing the tidal bore to see if it was possible to break the record.
"They knew exactly what they were doing. They are pros. They had been assessing the river for many years, but more specifically over the last three weeks," Champoux said.
He said the surfers had two Sea-Doos following them to provide assistance when needed.
Champoux said the surfers were not always on their feet. But at one point, he said Whitbread and Wessels were up on their feet surfing for 30 minutes together.
Boon for the tourism industry
Moncton is hoping to capitalize on new tourism money flowing into the city by people showing up to watch, and surf, on the tidal bore.
Wessels and Whitbread were among the four international surfers who travelled to Moncton this week to ride the tidal bore. Thousands of people have lined the banks of the Petitcodiac River throughout the week to watch them.
Champoux said he’s looking for some tips from the professional surfers on how to promote the river.
"Let's be honest, this is new to us. We don't pretend to be experts," Champoux said.
"We're going to rely on them to help us in terms of moving forward."
Richard Belliveau, a long-time Moncton-area resident, said the sight of surfers on the river, which was once blocked by a causeway, is amazing."I've been watching the tidal bore for 50 years, more, and that's the first time I've seen surfers," he said.
"So it's really quite exciting to see them do that. And also it's one of the highest bores in recent years. It's great."
Antony Colas has surfed the world’s biggest tidal bores and he said he has been waiting for years to travel from France to Moncton to check out the Petitcodiac River.
Last month, Colas watched an online video of the bore and decided it was time to catch a wave.
"I looked at the breaking wave, and was like, 'Oh it's back, it's back.' And within maybe days I took decision, bought a ticket, [told] my wife, 'Sorry I have to go for one week.' And basically it was a very last-minute decision and I'm not disappointed at all," he said.
He also had a direct message for all the onlookers on Wednesday.
"By the time the buzz will expand, in the month of August … you better surf at night because it's going to be too crowded during the day," he said.
The word of the growing waves on the Petitcodiac River is travelling fast in the region.
Tim Adham came from Nova Scotia on Wednesday to watch the surfers.
He said he hopes to surf the tidal bore with his daughter and he said he can see how this could be a big draw for the city.
"Everybody at the surf shop was like, what? No way, we want to hear about it, let us know how it goes. So it could take off," Adham said.
"But it's got to be organized by the city somehow, we don't know if we're actually allowed on the water."
The tidal bore has been growing in popularity following the decision to open the causeway gates in Moncton.
The decision to open the causeway gates was extremely controversial. The causeway was built in 1968 between Moncton and Riverview and the gates were opened in April 2010.