The Alolan Pokémon League is a competitive event in the Pokémon series, specifically set in the Alola region. It allows trainers to battle each other to prove their skills and earn the title of Champion. The league features various challenges, including battles against powerful trainers known as the Elite Four and the Champion. To participate, trainers must first complete the Island Trials, which test their abilities and knowledge of Pokémon. Once they have proven themselves, they can enter the league and face off against other skilled trainers in a series of battles, culminating in the ultimate showdown for the championship title.