It is only three years since the first Scottish Schools Triathlon Championships were staged but now it is one of the focal points of the race calendar. The sport is spreading to every corner of Scotland and there are many more races where children can test their athleticism.
Tomorrow, Edinburgh stages the British Duathlon Championships (run-cycle-run) in Holyrood Park. More than 600 athletes are expected to compete, including about 100 children.
There is an established aquathlon (swimming and running) series in Scotland for children, which is used as the first rung on the ladder for would-be triathletes. After this, children can progress to bring in cycling.
Over 40 senior triathlon clubs are established throughout Scotland now and, for the first time, this year there are three exclusively junior clubs set up to cater for the sport. One is based at Kinross High, one is at Davidsons Mains Primary in Edinburgh and one is in the LevenMethil area of Fife.
It is a development that Triathlon Scotland has seen coming. Last July, the governing body appointed a full-time development manager, John Lunn, to bring the many strands of junior competition together and he has found genuine enthusiasm for the sport in schools.
"The children view it as something different," he explains.
"The beauty of triathlon is that you are not expected to be excellent at swimming, cycling and running. Some children maybe can run well but not swim so strongly. Triathlon offers them a chance to make up ground in one part of the race."
There are two main ways in which children come into the sport, he says.
Either their parents are competing in triathlons and they want to try it, or they have seen the sport on television.
More than 100 triathlons will be staged throughout Scotland this year - a significant increase from last year - and many will include junior races.
Last year, 7,000 competitors' places were filled and that figure was about 1,500 up on the previous year.
September will be a key month. Galashiels will host the Scottish Schools Triathlon Championships and Glasgow will host the British Inter-Regional Triathlon Championships at Bellahouston Park. Mr Lunn sees this as an opportunity to get more children taking part.
"There will be a Glasgow's Tri-ing It programme," he explains, "and we expect there will be an aquathlon for primary schoolchildren, with just a 150m swim and a 1km run, so that they get a chance to try a competitive race.
"It will also give the children a chance to see the championships and the level they can possibly go on to attain."
Local authority leisure departments are taking an increasing interest in triathlon this year. Scottish Borders is staging a series of six triathlons - based around each one if its six swimming pools - and West Lothian plans to stage one in Broxburn.
John Dodds, who organised the Galashiels leg of the Borders series, says:
"It is a tremendous initiative and hopefully a lot more children will become involved after it."
The Stirling triathlon next month is one of the biggest on the race calendar, with 100 children expected to take part as well as almost 400 adults.
Such a race takes about 60 people to organise and steward. "I think clubs are willing to do it as it is the best way to attract people," says Mr Lunn.
Increasing participation is Mr Lunn's main emphasis at present, but talent identification is the natural progression and Triathlon Scotland is working on that with its high performance coach, John Dargie, and director of performance, Fiona Lothian, who were recently appointed.
There is a danger that promising schools triathletes could be lured to concentrate on one discipline of the sport, but Mr Lunn says: "We have worked hard to open doors with athletics, cycling and swimming as there is inevitably a cross-over between the sports. We think it is a good thing for children to be able to take part in different races, as it helps keep up their interest. We hope that swimmers, runners and cyclists will take part in our events in the same way our athletes race in theirs. It can only be a good thing that we open up lines of communication."
He adds: "We are looking to increase our coaching programme, as it is still very patchy.
"The three areas we are working most on are clubs, coaches and races."