A total of 695 people took up the offer of $10 adult and $5 children's tickets for high-speed trips through the Shotover Canyon.
Money raised from the day came to $6225, which means all Wakatipu High School Year 10 pupils will get the chance to go on next year's Branches camp.
Shotover Jet general manager Clark Scott said the adventure activity was fully booked for the rest of the day by 2.15pm.
Some residents had to be turned away.
The first trip at the Arthurs Point base of operations was at 7.45am and rides continued until about 6pm.
Mr Scott said the company was passionate about keeping the Branches camp going.
"It's been invaluable to our young people for more than 40 years and it would be a crying shame to see it go under because of funding issues.
"The camp has become a rite of passage for our Year 10 students.
"It's not just about getting them outdoors, it's about giving them a unique combination of life experiences and opportunities.
"The aim is to challenge them in all aspects of their lives in order to grow and shape who they are as adults and how they contribute to the society they live in.
"That's something you just cant put a price tag on."
Branches Charitable Trust chairwoman Kelly Campbell said the trust was "absolutely thrilled and very grateful".
"Shotover Jet's donation came completely out of the blue and has made a huge difference to our fundraising efforts.
"We're just blown away at how much they and the rest of the community have got behind our young people.
"We needed to raise $20,000 to be able to run the camp and had raised $12,000 to date.
"We knew we'd get a great boost from the proceeds of this weekend's Remarkables Christmas Spectacular and Santa's Grotto, but we thought we'd still have to do some serious fundraising after that, to meet our total.
"The $20,000 means that every Year 10 student gets the opportunity to go to Branches without more cost being loaded on to their parents."
Shotover Jet's Locals' Day has been held for more than 15 years.
In recent years the day has raised funds for various local causes.
