The Northern Irish singer teamed up with the U.K.'s When You Wish Upon a Star charity, which grants the wishes of children with life-threatening illnesses, for the wintry visit.
The youngsters made the trip to Lapland with their families to hand over their letters to Santa Claus, and Coyle was delighted to be part of the experience.
She tells Scotland's Daily Record newspaper, "It's hard to imagine what these families have gone through or put yourself in their position, so it's wonderful to be able to come along.
"It's fantastic that there are charities that do things like this. I'm glad to have the chance to support them."