His pace and sharp footwork saw him selected for the Ospreys in their British & Irish Cup campaign and international honours with Wales Under-20s soon followed.
He scored three tries as Wales claimed the Under-20s Grand Slam and had two more in the first game of the U20 World Rugby Championship in June.
Giles didn't complete the tournament however after being called up by Warren Gatland as injury cover for the senior squad during their tour of New Zealand.
"I've come through the pathway here, it's my home region, and I'm obviously delighted to have signed this contract," he said.
"It's been a pretty surreal year for me if I'm honest. I've achieved more than I could have hoped for and the Grand Slam was something I'm particularly proud of.
"It was a good year all-round, ending up with an unexpected call to go to New Zealand with the senior team, which was pretty incredible, and something I really enjoyed.
"Now I'm back home I want to kick on from where I am and keep improving."
Giles has put pen to paper on a three-year deal and Ospreys head coach Steve Tandy is excited by the potential of the young winger who, he says, still has plenty to improve on.
"Keelan is a young man who potentially has a very bright future ahead of him," Tandy said.
"His development over the last year or so has been impressive and is a sign of his character and attitude.
"Everyone who has seen him play will understand the talent he has but it's important to underline how young he still is and that he has a long way to go in terms of his development.
"He's still maturing, physically and mentally, and he's still coming to terms with the demands of senior rugby, so we've got to be careful in how we handle the next stage of his development if we want to get the best out of him in the long-term."
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