Running from July 6 to 12, the event will see Mark, 18, competing in the 50m, 100m and 200m backstroke and medley relay backstroke leg.
"Two years ago I got picked for the European Youth Olympic Festival,” Mark said.
"That was obviously a big honour to be picked for that team and to wear the Olympic rings on my chest.
"This is the next step up, European Juniors, my last competition as a junior.
"It’s great to be picked and I’m really happy with it. It’s going to be an exciting time and I’ll try and swim some fast times to try and make the Commonwealth Games next year.”