St John Cymru is undergoing a revamp to make it more appealing to young people.
St John says it is moving with the times
The charity, which trains volunteers in life-saving skills, said it was moving with the times and taking a fresh look at its young volunteers in Wales.
Around 100 youths from across the country are being introduced to a new range of exciting activities.
Project officer Michael Ford said the young persons' section was being modernised to have more appeal.
The organisation's cadet movement was introduced about 80 years ago.
Since then, there have been few changes to the way it tries to stimulate young members, whose ages range between five and 25.
Cadet of the year, Sarah Harries, 16, from Llanelli, said: "I think what St John is doing is fantastic.
"There's going to be more adventure and more outdoor activities and other things that have young people in mind. It's going to be much more fun."
She added: "I suppose St John is seen as a bit old fashioned and it needs to be modernised and it's doing that.
"There will also be some alterations to our uniforms."
The organisation is introducing a wide range of subjects from camping in the Brecon Beacons to learning sign language.
Importantly, it says, it is the young people who will decide which activities they want to explore.
Mr Ford said St John offered young people a fantastic opportunity.
"The old system was very rigid and didn't take into account people's ability or age," he added.
"The new programme is more flexible and takes into account people who have disabilities, so whatever their level or ability they should be able to take something away from it."
Cadet Sarah Harries says the new project was 'fantastic'
Mr Ford stressed that competition from outfits such as the Scouts, Girl Guides and the Army Cadets had made changes over the years and it was time for St John to do the same.
"St John is not just about first aid for young people, it's about maturing and developing them as people," he said.
"This is the biggest thing to happen to the youth movement within St John for decades.
"We felt the old system didn't fit into the new modern society."
St John is meeting in Brecon throughout Saturday.
St John Cymru has more than 5,500 volunteers who treat over 10,000 people annually.
More than 60% of the charity's young people in Wales are aged under 18.