Kate took over the role from her husband, Prince William, in December. Meanwhile, William made his debut as Colonel of the Welsh Guards in Windsor last week – a title previously held by his father, King Charles.
Stepping out in camo for the occasion, Kate helped to administer first aid to a wounded soldier as part of the battlefield exercise.
In the drill, members of the 1st Battalion Irish Guards were on foot patrol when they came under fire from an enemy. The exercise involved a soldier suffering a gunshot wound to his lower left leg and being evacuated from the scene by his colleagues.
The Princess assisted Lance Corporal Jodie Newell in administering first aid and applied a tourniquet to his lower left leg to stop the bleeding.
The soldier was then moved onto a stretcher where Kate helped with assessing him for further injuries to his torso.
Lance corporal Newell, 25, who was the soldier in charge of teaching the Princess first aid, described the situation as surreal.
“I was so nervous – I’m teaching the Princess of Wales med – it was an honour,” she said. “We were just showing her what we medics do in the Army – she was actually really good, really eager to take part.”
During her hands-on engagement, the Princess was taken on a tour of the Salisbury Plain training area by Major General Christopher Ghika, commander of the Army in London and the Household Division, and Lieutenant Colonel James Aldridge, commander of the 1st Battalion Irish Guards.
Kate, who was wearing brown Berghaus boots, heard first-hand about the work members of the battalion have undertaken recently, including meeting guardsmen who have been deployed on security work in Africa, which includes training park rangers on counter-poaching operations.
Lieutenant Colonel Aldridge said his battalion was delighted to welcome Kate to Salisbury Plain for her first visit as Royal Colonel.
He said: “It is particularly fitting on International Women’s Day that a few of our female soldiers met such an inspiring female role model.
“It is a real honour for all the guardsmen to meet their Royal Colonel in the field here on Salisbury Plain and demonstrate a few of our basic operational skills.”
Kate later said in an Instagram post: “A snowy morning with the @irishguards on Salisbury Plain! The work of the Irish Guards is as wide-ranging as it is exemplary, from training park rangers on counter-poaching in East Africa to de-mining training for Ukrainian Armed Forces. Fantastic to be with ‘The Micks’ today seeing their hard work (whatever the weather!)”
When William held the role, he and Kate would attend the annual St Patrick’s Day parade, with the Princess handing out shamrocks to the officers.