Around 140 members of the regiment of army reservists took part in a parade on the lawn at Bramham Park House, Wetherby, on Saturday (Sept 22)
Charles, wearing his ceremonial frock coat and sword, chatted to troops during an inspection before presenting a new Guidon military standard to the commanding officer and regiment.
Warrant Officer Second Class David William, who marched the old standard off and the new one on, said it was an "honour".
He added: "It was a wonderful opportunity to meet the prince, he joked about the fact that the weather has improved."
Full-time reservist Captain Timothy Miller, 37, of Kirkstall, Leeds, who saw active service during a six-month tour of Afghanistan in 2011, said: "It was incredible.
"It was the first time the majority of serving soldiers have ever experienced a parade of this scale.
"Nobody enjoys preparing for a parade like this because it is long hours rehearsing.
"But on the day everyone forgets the hard work and as soon as the drum beats and you start marching you are full of pride and honour for the regiment."
Charles said in a speech: "This is the second time you have been presented with a Guidon since the formation of the Regiment in 1971, forty-seven years ago.
"The Guidon that has been marched off parade today represents over two centuries of volunteer service to the Crown at home and abroad; service which has continued to this day.
"Since its formation, the regiment has carried on the example of its forebears and served around the world on exercises and operations.
"As Your Royal Honorary Colonel, I am so very proud to witness the Queen’s Own Yeomanry continuing to uphold its traditions of service and duty whilst meeting the new challenges of an ever-changing world.
"I acknowledge with immense gratitude and undying admiration the truly exceptional contribution that your Officers, Soldiers and families provide so selflessly to the defence of the realm. You set us an outstanding example that I, for one, do not take for granted.
"For instance, since 2006, 124 yeomen from the Queen’s Own Yeomanry have been mobilised in support of twenty-five different deployments, including to Iraq, Afghanistan, Cyprus and, most recently, Poland on NATO’s Eastern flank.
"As I speak, many Army reservists will be engaged on continuously hazardous operations, often out of sight and out of mind. Many will be called upon to leave their civilian workplaces to return to dangerous theatres of operation.
"This kind of remarkable loyalty and dedication cannot be realised without the selfless and extraordinary support of reservists’ families. I would like to take this opportunity today to salute them for the vital and understanding role they play.
"You should all be justifiably proud of your achievements to date and I have every confidence that with the strength derived from your illustrious forebears, and from this new Guidon, the regiment will go from strength to strength.
"I can only congratulate you today on the smartness of your bearing and on all the effort you have put into this splendid occasion.
"On behalf of Her Majesty, I am entrusting this new Guidon, which chronicles so much of the regiment’s marvellous History, to your safekeeping, and I am certain that it will inspire all those who serve alongside it to maintain the very highest standards in the Queen’s Own Yeomanry.”
Charles has been the Royal Honorary Colonel of the Queen's Own Yeomanry since 2000.