Snowboarding is a new mini-game introduced in The Legend of Heroes: Trails of Cold Steel II, located only in Ymir. It eventually opens up later in the story, with item rewards for grabbing flags on the way down and under the time limit. As the story progresses, new difficult levels are unlocked. The player can eventually unlock additional snowboards, purely for cosmetic effect.
Snowboarding provides some useful prizes, but is never required to play. There are also no Trophies associated with this mini-game.