The 21-year-old star was in North Lanarkshire to celebrate the success of Scottish Swimming’s Learn to Swim programme.
During his session he raced youngsters in a knockout competition.
And local club swimmers Michael Flynn (15) and Euan Macdonald (16) proved they are potentially ready to be the next big names in Scotland by taking on the Olympic Games, World and European Championship and Commonwealth Games medallist.
Michael, a pupil from Cumbernauld High School, said: “It was pretty cool being able to race such a big athlete.
“The kids today were all super excited to meet them – he’s a role model.
And Euan, who studies at Our Lady’s High School, said: “Who knows, if we keep training hard, we might be able to beat him one day!”
Duncan, who takes on the role of Learn to Swim Ambassador, also shared his top tips and tricks with the local children in a Q&A session.
Scottish Swimming’s National Learn to Swim Framework is supported by Scottish Water and delivered by Leisure Trusts and aquatic providers across Scotland.
The initiative is already helping 5,500 kids in the region to learn to swim.
Duncan said: “Euan and Michael sure were impressive swimmers.
“And there were some other close contenders! It’s great to see how much the kids in North Lanarkshire love the sport.”
Duncan won six medals at the Gold Coast Commonwealth Games in Australia last year – the most medals which have ever been won by a Scottish athlete at a single Games.
His other achievements include becoming Scotland’s Sportsperson of the Year and Swimming Athlete of the Year for 2018.
Emma Walker, managing director at North Lanarkshire Leisure, said: “Everyone had such a fantastic time meeting Duncan and showcasing what these swimming lessons have to offer – the launch has definitely instilled a newfound love for the sport.”
Forbes Dunlop, CEO of Scottish Swimming, said: “Swimming is so much more than just a sport – it’s a key life skill.
“That’s why we’re aiming to reach over 100,000 children across Scotland with this framework by 2020.”
A recent study of the impact of the Learn to Swim Framework found it had overwhelming approval from the parents across the country.
Brian Lironi, Director of Corporate Affairs for Scottish Water, said: “We’re surrounded by so much water in Scotland that it’s essential to learn to swim from a young age.
“We’re proud to support this programme as we aim to build a confident and safe generation of swimmers.”